<Page>

                                                                     Exhibit 1.1



                                1,240,000 SHARES

                        CORPORATE OFFICE PROPERTIES TRUST

  9 7/8% SERIES F CUMULATIVE REDEEMABLE PREFERRED SHARES OF BENEFICIAL INTEREST
                    (LIQUIDATION PREFERENCE $25.00 PER SHARE)
                             UNDERWRITING AGREEMENT

                                                               September 6, 2001

CREDIT SUISSE FIRST BOSTON CORPORATION
A.G. EDWARDS & SONS, INC.
     As Representatives of the Several Underwriters (the "Representatives"),
     c/o Credit Suisse First Boston Corporation,
         Eleven Madison Avenue,
         New York, N.Y. 10010-3629

Dear Sirs:

     1.   INTRODUCTORY. Corporate Office Properties Trust, a Maryland real
estate investment trust ("COMPANY"), proposes to issue and sell 1,240,000 ("FIRM
SECURITIES") of its 9.875% Series F Cumulative Redeemable Preferred Shares of
Beneficial Interest (Liquidation Preference $25.00 Per Share), par value $.01
per share ("SECURITIES"), and also proposes to issue and sell to the
Underwriters, at the option of the Underwriters, an aggregate of not more than
185,000 additional shares ("OPTIONAL SECURITIES") of its Securities as set forth
below. The Firm Securities and the Optional Securities are herein collectively
called the "OFFERED SECURITIES." The Company and Corporate Office Properties,
L.P., a Delaware limited partnership ("OPERATING PARTNERSHIP"), hereby agree
with the several Underwriters named in Schedule I hereto ("UNDERWRITERS") as
follows:

     2.   REPRESENTATIONS AND WARRANTIES OF THE COMPANY AND THE OPERATING
PARTNERSHIP. The Company and the Operating Partnership represent and warrant to,
and agree with, the several Underwriters that:

          (a)  A registration statement (No. 333-71807) relating to the Offered
     Securities, including a base prospectus, has been filed with the Securities
     and Exchange Commission (the "COMMISSION") under the Securities Act of
     1933, as amended ("ACT") and such registration statement ("INITIAL
     REGISTRATION STATEMENT") has been declared effective. A post-effective
     amendment to the initial registration statement, including a base
     prospectus dated November 1, 2000 (the "BASE PROSPECTUS"), has also been
     filed and declared effective under the Act. For purposes of this Agreement,
     "EFFECTIVE TIME" with respect to the initial registration statement means
     the date and time as of which the most recent post-effective amendment
     thereto filed prior to the execution and delivery of this Agreement, was
     declared effective by the Commission. "EFFECTIVE DATE" with respect to the
     initial registration statement means the date of the Effective Time
     thereof. The initial registration statement, as amended at its Effective
     Time, including all material incorporated by reference therein, pursuant to
     the General Instructions of the Form on which it is filed and including all
     information (if any) deemed to be a part of the initial registration
     statement as of its Effective Time pursuant to Rule 430A(b) ("RULE
     430A(b)") under the Act, is hereinafter referred to as the "REGISTRATION
     STATEMENT." The Base Prospectus, together with the final prospectus
     supplement setting forth the final terms of the offering, sale and plan of
     distribution of the Offered Securities, as filed with the Commission
     pursuant to and in accordance with Rule 424(b) ("RULE 424(b)") under the
     Act or (if no such filing is required) as included in a Registration
     Statement, including all material incorporated by reference in such
     prospectus, is hereinafter referred to as the "PROSPECTUS." References to a
     "preliminary


<Page>

     prospectus" mean the Base Prospectus together with the preliminary
     prospectus supplement relating to the Offered Securities. No document has
     been or will be prepared or distributed in reliance on Rule 434 under the
     Act. The Company meets the requirements for the use of Form S-3 under the
     Act and the Registration Statement meets the requirements of, and complies
     in all material respects with, Rule 415(a)(1)(x) under the Act.

          (b)  If the Effective Time of the Registration Statement is prior to
     the execution and delivery of this Agreement: (i) on the Effective Date of
     the Registration Statement, the Registration Statement conformed in all
     respects to the requirements of the Act and the rules and regulations of
     the Commission ("RULES AND REGULATIONS") and did not include any untrue
     statement of a material fact or omit to state any material fact required to
     be stated therein or necessary to make the statements therein not
     misleading and (ii) on the date of this Agreement, the Registration
     Statement conforms, and at the time of filing of the Prospectus pursuant to
     Rule 424(b) the Registration Statement and the Prospectus will conform, in
     all material respects, to the requirements of the Act and the Rules and
     Regulations, and neither of such documents includes, or will include, any
     untrue statement of a material fact or omits, or will omit, to state any
     material fact required to be stated therein or necessary to make the
     statements therein not misleading, and with respect to the Prospectus only,
     in light of the circumstances in which they were made. The preceding
     sentence does not apply to statements in or omissions from a Registration
     Statement or the Prospectus based upon written information furnished to the
     Company by any Underwriter through the Representatives specifically for use
     therein, it being understood and agreed that the only such information is
     that described as such in Section 7(b) hereof.

          (c)  No stop order suspending the effectiveness of the Registration
     Statement or any part thereof has been issued and, to the knowledge of the
     Company, no proceeding for that purpose has been instituted or threatened
     by the Commission or by the state securities authority of any jurisdiction.
     No order preventing or suspending the use of the Prospectus has been issued
     and, to the knowledge of the Company, no proceeding for that purpose has
     been instituted or threatened by the Commission or by the state securities
     authority of any jurisdiction.

          (d)  The Company has been duly organized and is an existing real
     estate investment trust in good standing under the laws of the State of
     Maryland, with power and authority as a real estate investment trust to own
     its properties and conduct its business as described in the Prospectus; and
     the Company is duly qualified to do business as a foreign corporation in
     good standing in all other jurisdictions in which its ownership or lease of
     property or the conduct of its business requires such qualification, except
     where the failure to be so qualified would not reasonably be expected to
     have a material adverse effect on (i) the condition (financial or other),
     business, properties, prospects, net worth or results of operations of the
     Company and its Subsidiaries (as hereinafter defined) taken as a whole,
     (ii) the issuance, validity or enforceability of the Offered Securities or
     (iii) the consummation of any of the transactions contemplated by this
     Agreement to be performed by the Company and/or the Subsidiaries
     (individually or collectively, a "MATERIAL ADVERSE EFFECT").

          (e)  Each subsidiary of the Company listed on Schedule II hereto
     ("SUBSIDIARIES") has been duly organized and is validly existing as a
     corporation, limited partnership or other legal entity, as the case may be,
     in good standing under the laws of its respective jurisdictions of
     incorporation or formation, with power and authority (corporate and other)
     to own its properties and conduct its business as described in the
     Prospectus; and each Subsidiary is duly qualified to do business as a
     foreign corporation, limited partnership or other legal entity, as the case
     may be, in good standing in all other jurisdictions in which such
     Subsidiary's ownership or lease of property or the conduct of such
     Subsidiary's business requires such qualification, except where the failure
     to be so qualified would not reasonably be expected


<Page>

     to have a Material Adverse Effect. The issued and outstanding common and
     preferred units of limited partnership interest in the Operating
     Partnership ("UNITS") and other equity interests, as the case may be, of
     each of the Company's other Subsidiaries have been duly authorized and
     validly issued, are, with respect to corporate Subsidiaries, fully paid and
     nonassessable and, except as otherwise set forth in the Prospectus or
     reflected in the financial statements contained in, or incorporated by
     reference in, the Prospectus, are owned beneficially by the Company,
     directly or indirectly through one or more Subsidiaries, free and clear of
     any security interests, liens, encumbrances, equities or claims, except for
     security interests, liens, encumbrances, equities or claims pursuant to the
     terms of a bona fide financing transaction.

          (f)  Complete and correct copies of the declaration of trust and of
     the bylaws of the Company, the certificate of limited partnership and
     agreement of limited partnership of the Operating Partnership and the
     charter documents, partnership agreements and other organizational
     documents of the other Subsidiaries, as applicable, and all amendments
     thereto as have been requested by the Underwriters or their counsel have
     been delivered to the Underwriters or their counsel. As of the Closing Date
     (as hereinafter defined), the partnership agreement of the Operating
     Partnership, as amended, will have been duly authorized, executed and
     delivered by the Company, as the general partner and as a limited partner
     and (assuming it has been duly authorized, executed and delivered by each
     of the other parties thereto, and is a legal, valid and binding agreement
     of each such other party) in full force and effect, subject to (i) the
     effect of bankruptcy, insolvency, fraudulent conveyance, reorganization,
     moratorium or other similar laws now or hereafter in effect relating to or
     affecting the rights and remedies of creditors, (ii) the effect of general
     principles of equity, whether enforcement is considered in a proceeding in
     equity or at law, and the discretion of the court before which any
     proceeding therefore may be brought and (iii) the provisions of the
     Delaware Revised Uniform Limited Partnership Act.

          (g)  The Company has an authorized, issued and outstanding
     capitalization as set forth in the Prospectus. All of the issued and
     outstanding shares of beneficial interest of the Company have been duly
     authorized and validly issued and are fully paid and nonassessable. The
     Offered Securities have been duly authorized and, when the Offered
     Securities have been delivered and paid for in accordance with this
     Agreement on each Closing Date (as hereinafter defined), such Offered
     Securities will have been validly issued, fully paid and nonassessable and
     will conform to the description thereof contained in the Prospectus and the
     description contained in the articles supplementary determining the terms
     of the Offered Securities ("ARTICLES SUPPLEMENTARY"), and at the First
     Closing Date (as hereinafter defined) and Optional Closing Date (as
     hereinafter defined), such descriptions will be, complete and accurate in
     all material respects; the stockholders of the Company have no preemptive
     rights with respect to the Offered Securities; and no holder of securities
     of the Company has any right which has not been fully exercised or waived
     to require the Company to register the offer or sale of any securities
     owned by such holder under the Act in the public offering contemplated by
     this Agreement.

          (h)  Except as disclosed in the Prospectus or not disclosed because
     not material, the Company and its Subsidiaries do not have outstanding, and
     at the First Closing Date and Optional Closing Date will not have
     outstanding (A) securities or obligations of the Company or any of its
     Subsidiaries convertible into or exchangeable for any shares of beneficial
     interest of the Company or any such Subsidiary, (B) warrants, rights or
     options to subscribe for or purchase from the Company or any such
     Subsidiary any such shares of beneficial interest or any such convertible
     or exchangeable securities or obligations, or (C) obligations of the
     Company or any such Subsidiary to issue any shares of beneficial interest,
     any such convertible or exchangeable securities or obligations, or any such
     warrants, rights or options. Upon payment of the purchase price and
     delivery of certificates evidencing the Offered Securities in accordance
     herewith, the Underwriters will receive good, valid and marketable title to
     the Offered Securities, free and clear of all security interests,
     mortgages, pledges, liens, encumbrances, claims and equities. The form



<Page>

     of share certificates to be used to evidence the Offered Securities will be
     in due and proper form and will comply, in all material respects, with all
     applicable legal requirements. Other than shares of beneficial interest of
     the Company issuable upon (i) exercise of share options pursuant to the
     Company's stock-based plans for its employees and trustees, (ii) upon the
     redemption of Units, (iii) in connection with certain limited partnership
     interests in limited partnerships holding certain office properties
     retained by Shidler Equities, L.P. and Clay W. Hamlin, III, or (iv) in
     connection with the conversion of either of the 5.5% Series A Convertible
     Preferred Share of Beneficial Interest, or the 4% Series D Convertible
     Preferred Shares of Beneficial Interest of the Company into Common Shares
     of Beneficial Interest of the Company, no shares of beneficial interest of
     the Company are reserved for any purpose, except as disclosed in the
     Prospectus.

          (i)  The execution, delivery and performance of this Agreement by the
     Company and the Operating Partnership, the issuance, offering and sale of
     the Offered Securities to the Underwriters by the Company pursuant to this
     Agreement, the execution and recording of the Articles Supplementary by the
     Company and the compliance by the Company and the Operating Partnership
     with the other provisions of this Agreement and the consummation of the
     other transactions herein contemplated do not (i) require any material
     governmental license, permit, consent, approval, authorization or other
     order of, registration, filing or qualification with, any court or
     governmental body or agency (except for the filing of the Articles
     Supplementary with the State Department of Assessments and Taxation of
     Maryland ("SDAT"), which filing with the SDAT will be made prior to the
     First Closing Date, and except such as have been obtained or may be
     required under the Act and the Securities Exchange Act of 1934, as amended
     (the "EXCHANGE ACT"), securities, blue sky or real estate syndication laws
     of the various states, the bylaws and rules of the National Association of
     Securities Dealers, Inc. ("NASD") or the requirements of the NYSE), (ii)
     result in the creation or imposition of any lien, charge or encumbrance
     upon any of the assets or properties of the Company or any of the
     Subsidiaries pursuant to the terms or provisions of, or conflict with or
     constitute a breach or violation of any of the terms or provisions of, or a
     default under (and there is no event which, but for the passage of time or
     the giving of notice, or both, would constitute a default under any of the
     foregoing), or give any other party a right to terminate any of its
     obligations under, or result in the acceleration of any obligation under,
     the charter, declaration of trust, bylaws, partnership agreement or other
     organizational document of the Company or any of the Subsidiaries or in the
     performance or observance of any obligation, covenant, agreement or
     condition contained in any indenture, loan agreement, mortgage, bond,
     debenture, note agreement, joint venture or partnership agreement, lease or
     other agreement or instrument that is material to the Company and the
     Subsidiaries, taken as a whole, to which the Company or any of the
     Subsidiaries is a party or by which the Company or any of the Subsidiaries
     or their respective property is bound or, (iii) violate or conflict with
     any applicable law or any rule, regulation, judgment, order, statute,
     administrative regulation or decree of any court or any governmental body
     or agency (foreign or domestic) having jurisdiction over the Company, any
     of the Subsidiaries or their respective property, in each case except for
     liens, charges, encumbrances, breaches, violations, defaults, rights to
     terminate or accelerate obligations, or conflicts, the imposition or
     occurrence of which would not have a Material Adverse Effect.

          (j)  Each of the Company and the Operating Partnership has full trust
     or partnership power, as the case may be, to enter into this Agreement, and
     to carry out all of the terms and provisions hereof to be carried out by
     them. This Agreement has been duly and validly authorized, executed and
     delivered by each of the Company and the Operating Partnership, and
     constitutes a valid and binding agreement of each of the Company and the
     Operating Partnership, and assuming due authorization, execution and
     delivery by the Underwriters, is enforceable against the Company and the
     Operating Partnership, in accordance with the terms hereof subject to (i)
     the effect of bankruptcy, insolvency, fraudulent conveyance,
     reorganization, moratorium or other similar laws now or hereafter in effect
     relating to or affecting the rights and remedies of


<Page>

     creditors and (ii) the effect of general principles of equity, whether
     enforcement is considered in a proceeding in equity or at law, and the
     discretion of the court before which any proceeding therefor may be
     brought. The Articles Supplementary have been duly and validly authorized,
     executed and delivered by the Company, and are in full force and effect,
     subject to (i) the effect of bankruptcy, insolvency, fraudulent conveyance,
     reorganization, moratorium or other similar laws now or hereafter in effect
     relating to or affecting the rights and remedies of creditors and (ii) the
     effect of general principles of equity, whether enforcement is considered
     in a proceeding in equity or at law, and the discretion of the court before
     which any proceeding therefor may be brought.

          (k)  When the Offered Securities are delivered and paid for pursuant
     to this Agreement on each Closing Date, the Company and each of its
     Subsidiaries will have good and marketable title in fee simple to all items
     of real property and good and marketable title to all personal property and
     assets owned by each of them, in each case free and clear of any security
     interests, liens, encumbrances, equities, claims and other defects, except
     such as where the failure to have such title would not result in a Material
     Adverse Effect or do not materially and adversely affect the value of such
     property or materially interfere with the use made or proposed to be made
     of such property by the Company or such Subsidiary (except in each case
     liens securing indebtedness of the Company or its Subsidiaries as reflected
     in its financial statements included in the Prospectus), and any real
     property and buildings held under lease by the Company or any such
     Subsidiary are held under valid, subsisting and enforceable leases, except
     which would not result in a Material Adverse Effect or do not materially
     interfere with the use made or proposed to be made of such property and
     buildings by the Company or such Subsidiary, in each case except as
     described in or contemplated by the Prospectus. To the knowledge of the
     Company and the Operating Partnership: (i) no lessee of any portion of the
     properties is in material default under any of the leases governing such
     properties and there is no event which, but for the passage of time or the
     giving of notice, or both, would constitute a default under any of such
     leases, except in each case such defaults that would not have a Material
     Adverse Effect; (ii) the current use and occupancy of each of the
     properties complies in all material respects with all applicable codes and
     zoning laws and regulations, except for such failures to comply which would
     not individually or in the aggregate have a Material Adverse Effect; and
     (iii) there is no pending or threatened condemnation, zoning change,
     environmental or other proceeding or action that will in any material
     respect affect the size of, use of, improvements on, construction on, or
     access to the properties except such proceedings or actions that would not
     have a Material Adverse Effect.

          (l)  The Company and its Subsidiaries possess adequate certificates,
     authorities, consents, authorizations or permits issued by appropriate
     governmental agencies or bodies necessary to conduct the business now
     operated by them, have complied, in all material respects, with the laws,
     regulations and orders known by them to be applicable to them or their
     respective businesses and properties and have not received any notice of
     proceedings relating to the revocation or modification of any such
     certificate, authority, consents, authorizations or permit that, if
     determined adversely to the Company or any of its Subsidiaries, would
     individually or in the aggregate have a Material Adverse Effect.

          (m)  No labor dispute with the employees of the Company or any
     Subsidiary exists or, to the knowledge of the Company, is threatened or
     imminent that might have a Material Adverse Effect.

          (n)  The Company and its Subsidiaries own, possess, license or can
     acquire on reasonable terms, adequate trademarks, trade names, licenses,
     and other rights to inventions, know-how, patents, copyrights, confidential
     or proprietary information and other intellectual property (collectively,
     "INTELLECTUAL PROPERTY RIGHTS") necessary to conduct the business now
     operated by them, or presently employed by them, and have not received any
     notice of


<Page>


     infringement of or conflict with asserted rights of others with respect
     to any intellectual property rights that, if determined adversely to the
     Company or any of its Subsidiaries, would individually or in the aggregate
     have a Material Adverse Effect.

          (o)  Except for activities, conditions, circumstances or matters that
     would not have a Material Adverse Effect, (A) to the knowledge of the
     Company, after due inquiry, neither the Company nor any of the Subsidiaries
     has violated (i) any foreign, federal, state or local law or regulation
     relating to the protection of human health and safety, the environment or
     hazardous or toxic substances or wastes, pollutants or contaminants
     ("ENVIRONMENTAL LAWS") (and the Company and the Subsidiaries are in
     compliance with all requirements of applicable permits, licenses, approvals
     or other Authorizations issued pursuant to Environmental Laws), (ii) any
     provisions of the Employee Retirement Income Security Act of 1974, as
     amended or (iii) any provisions of the Foreign Corrupt Practices Act, or
     the rules and regulations promulgated thereunder; (B) to the knowledge of
     the Company and the Subsidiaries, after due inquiry, none of the Company or
     the Subsidiaries has caused or suffered to occur any Release (as
     hereinafter defined) of any Hazardous Substance (as hereinafter defined)
     into the Environment (as hereinafter defined) on, in, under or from any
     property, and no condition exists on, in, under or adjacent to any property
     that would reasonably be expected to result in the incurrence of
     liabilities under, or any violations of, any Environmental Law or give rise
     to the imposition of any Lien (as hereinafter defined), under any
     Environmental Law; (C) none of the Company or the Subsidiaries has received
     any written notice of a material claim under or pursuant to any
     Environmental Law or under common law pertaining to Hazardous Substances
     on, in, under or originating from any property; (D) none of the Company or
     any of the Subsidiaries has actual knowledge of, or received any written
     notice from any Governmental Authority (as hereinafter defined) claiming,
     any material violation of any Environmental Law or a determination to
     undertake and/or request the investigation, remediation, clean-up or
     removal of any Hazardous Substance released into the Environment on, in,
     under or from any property; and (E) no property is included or, to the
     knowledge of the Company and the Subsidiaries, after due inquiry, proposed
     for inclusion on the National Priorities List issued pursuant to CERCLA (as
     hereinafter defined) by the United States Environmental Protection Agency
     (the "EPA"), or included on the Comprehensive Environmental Response,
     Compensation, and Liability Information System database maintained by the
     EPA, and none of the Company and the Subsidiaries has actual knowledge that
     any property has otherwise been identified in a published writing by the
     EPA as a potential CERCLA removal, remedial or response site or, to the
     knowledge of the Company and the Subsidiaries, is included on any similar
     list of potentially contaminated sites pursuant to any other Environmental
     Law.

          As used herein, "HAZARDOUS SUBSTANCE" shall include any hazardous
     substance, hazardous waste, toxic substance, pollutant or hazardous
     material, including, without limitation, oil, petroleum or any
     petroleum-derived substance or waste, asbestos or asbestos-containing
     materials, PCBs, pesticides, explosives, radioactive materials, dioxins,
     urea formaldehyde insulation or any constituent of any such substance,
     pollutant or waste which is subject to regulation under any
     Environmental Law (including, without limitation, materials listed in
     the United States Department of Transportation Optional Hazardous
     Material Table, 49 C.F.R. Section 172.101, or in the EPA's List of
     Hazardous Substances and Reportable Quantities, 40 C.F.R. Part 302);
     "ENVIRONMENT" shall mean any surface water, drinking water, ground
     water, land surface, subsurface strata, river sediment, buildings,
     structures, and indoor and outdoor air; "ENVIRONMENTAL LAW" shall mean
     the Comprehensive Environmental Response, Compensation and Liability Act
     of 1980, as amended (42 U.S.C. Section 9601 et seq.) ("CERCLA"), the
     Resource Conservation and Recovery Act of 1976, as amended (42 U.S.C.
     Section 6901, et seq.), the Clean Air Act, as amended (42 U.S.C. Section
     7401, et seq.), the Clean Water Act, as amended (33 U.S.C. Section 1251,
     et seq.), the Toxic Substances Control Act, as amended (15 U.S.C.
     Section 2601, et seq.), the Occupational Safety and Health Act of 1970,
     as amended (29 U.S.C. Section 651, et seq.), the

<Page>

     Hazardous Materials Transportation Act, as amended (49 U.S.C. Section 1801,
     et seq.), and all other federal, state and local laws, ordinances,
     regulations, rules and orders relating to the protection of the environment
     or of human health from environmental effects; "GOVERNMENTAL AUTHORITY"
     shall mean any federal, state or local governmental office, agency or
     authority having the duty or authority to promulgate, implement or enforce
     any Environmental Law; "LIEN" shall mean, with respect to any property, any
     mortgage, deed of trust, pledge, security interest, lien, encumbrance,
     penalty, fine, charge, assessment, judgment or other liability in, on or
     affecting such property; and "RELEASE" shall mean any spilling, leaking,
     pumping, pouring, emitting, emptying, discharging, injecting, escaping,
     leaching, dumping, emanating or disposing of any Hazardous Substance into
     the Environment, including, without limitation, the abandonment or discard
     of barrels, containers, tanks (including, without limitation, underground
     storage tanks) or other receptacles containing or previously containing and
     containing a residue of any Hazardous Substance.

          (p)  To the knowledge of the Company, none of the environmental
     consultants which prepared environmental and asbestos inspection reports
     with respect to any of the properties was employed for such purpose on a
     contingent basis or has any substantial interest in the Company or any of
     the Subsidiaries, and none of them nor any of their directors, officers or
     employees is connected with the Company or any of the Subsidiaries as a
     promoter, selling agent, voting trustee, director, officer or employee.

          (q)  Except as disclosed in the Prospectus, after due inquiry, there
     are no pending actions, suits or proceedings against or, to the knowledge
     of the Company, affecting the Company, any of its Subsidiaries or any of
     their respective properties or any of their respective officers or trustees
     that, if determined adversely to the Company or any of its Subsidiaries or
     any of their respective officers or trustees, would individually or in the
     aggregate have a Material Adverse Effect, or would materially and adversely
     affect the ability of the Company to perform its obligations under this
     Agreement, or which are otherwise material in the context of the sale of
     the Offered Securities and/or are required to be described in the
     Registration Statement or Prospectus; and, to the knowledge of the Company,
     no such actions, suits or proceedings are threatened or contemplated, in
     each case, before or by any federal or state court, commission, regulatory
     body, administrative agency or other governmental body, domestic or
     foreign, having jurisdiction over the Company, any of its Subsidiaries or
     assets; and no contract, statute, regulation or other document is required
     to be described in the Registration Statement or the Prospectus or to be
     filed as an exhibit to the Registration Statement that is not described
     therein or filed as required.

          (r)  The consolidated financial statements and schedules and notes
     thereto of the Company and its consolidated Subsidiaries included in the
     Registration Statement and the Prospectus comply in all material respects
     with the requirements of the Act and the Exchange Act, as applicable, and
     fairly present the financial position of the Company and its consolidated
     Subsidiaries and the results of operations and changes in financial
     condition as of the dates and periods therein specified. Such financial
     statements, schedules and notes have been prepared in accordance with
     generally accepted accounting principles consistently applied throughout
     the periods involved (except as otherwise noted therein). The selected
     financial data set forth under the caption "Selected Financial Information"
     in the Prospectus fairly present, on the basis stated in the Prospectus,
     the information included therein. Except as otherwise noted in the
     Prospectus, as adjusted financial information included in the Prospectus
     has been prepared in accordance with the applicable requirements of the Act
     and the American Institute of Certified Public Accountants guidelines with
     respect to as adjusted financial information, and includes where required
     all adjustments necessary to present fairly the as adjusted financial
     condition of the Company and the Subsidiaries presented or included at the
     respective dates indicated and the results of operations and cash flows for
     the respective periods specified; and the assumptions used in preparing the
     as adjusted financial statements included in the Registration Statement and
     the Prospectus provide a


<Page>

     reasonable basis for presenting the significant effects directly
     attributable to the transactions or events described therein, the related
     as adjusted adjustments give appropriate effect to those assumptions, and
     the as adjusted columns therein reflect the proper application of those
     adjustments to the corresponding historical financial statement amounts. No
     other financial statements (or schedules) of the Company or any predecessor
     of the Company are required by the Act to be included in the Registration
     Statement or the Prospectus.

          (s)  PricewaterhouseCoopers LLP, who have certified certain financial
     statements of the Company and its consolidated subsidiaries and delivered
     their report with respect to the audited consolidated financial statements
     and schedules included in the Registration Statement and the Prospectus,
     are independent public accountants as required by the Act and the Exchange
     Act.

          (t)  Subsequent to the respective dates as of which information is
     given in the Registration Statement or the Prospectus and prior to the
     First Closing Date, (i) neither the Company nor any of its Subsidiaries has
     sustained any material casualty loss, condemnations or interference with
     their respective businesses or properties from fire, flood, hurricane,
     accident or other calamity, whether or not covered by insurance, or from
     any labor dispute or any legal or governmental proceeding, (ii) there has
     not been any material adverse change, or any development or event that
     would be reasonably likely to result in a material adverse change, in the
     condition (financial or otherwise), management, business, properties,
     prospects, net worth, or results of operations of the Company or any of its
     Subsidiaries, taken as a whole, except in each case as described in or
     contemplated by the Prospectus and (iii) except as disclosed in or
     contemplated by the Prospectus or otherwise consistent with past practice,
     there has been no dividend or distribution of any kind declared, paid or
     made by the Company on any class of its capital stock.

          (u)  The Company is not and, after giving effect to the offering and
     sale of the Offered Securities and the application of the proceeds thereof
     as described in the Prospectus, will not be an "investment company" as
     defined in the Investment Company Act of 1940, as amended.

          (v)  The Company has not, directly or indirectly, (i) taken any action
     designed to cause or to result in, or that has constituted or which might
     reasonably be expected to constitute, the stabilization or manipulation of
     the price of any security of the Company to facilitate the sale or resale
     of the Offered Securities or (ii) since the filing of the Registration
     Statement (A) sold, bid for, purchased, or paid anyone any compensation for
     soliciting purchases of, the Offered Securities or (B) paid or agreed to
     pay to any person any compensation for soliciting another to purchase any
     other securities of the Company.

          (w)  The Company has not distributed and, prior to the later of
     (i) the First Closing Date and (ii) the completion of the distribution of
     the Offered Securities, will not distribute any offering material in
     connection with the offering and sale of the Offered Securities other than
     the Registration Statement or any amendment thereto, or the Prospectus or
     any amendment or supplement thereto, or other materials, if any permitted
     by the Act.

          (x)  Subsequent to the respective dates as of which information is
     given in the Registration Statement and the Prospectus, (1) the Company and
     its Subsidiaries have not incurred any material liability or obligation,
     direct or contingent, nor entered into any material transaction, in each
     case, not in the ordinary course of business; (2) the Company has not
     purchased any of its outstanding shares of beneficial interest, nor
     declared, paid or otherwise made any dividend or distribution of any kind
     on its shares of beneficial interest except in the ordinary course of
     business consistent with past practices; and (3) there has not been any
     material


<Page>

     change in the capitalization, equity, short-term debt or long-term debt of
     the Company and its consolidated Subsidiaries, except in each case as
     described in or contemplated by the Prospectus.

          (y)  The Company and each of its Subsidiaries are insured by property,
     title, casualty and liability insurers of recognized financial
     responsibility against such losses and risks and in such amounts as are
     prudent and customary in the businesses in which they are engaged; neither
     the Company nor any such Subsidiary has been refused any insurance coverage
     sought or applied for; and neither the Company nor any such Subsidiary has
     any reason to believe that it will not be able to renew its existing
     insurance coverage as and when such coverage expires or to obtain similar
     coverage from similar insurers as may be necessary to continue its business
     at a cost that would not result in Material Adverse Effect, except in such
     instances where the tenant is carrying such insurance or the tenant is
     self-insuring such risks and except as described in or contemplated by the
     Prospectus.

          (z)  No Subsidiary of the Company is currently prohibited, directly or
     indirectly, from paying any dividends to the Company, from making any other
     distribution on the equity interest in such Subsidiary held by the Company,
     from repaying to the Company any loans or advances to such Subsidiary from
     the Company or from transferring any of such Subsidiary's property or
     assets to the Company or any other Subsidiary of the Company, except as
     described in or contemplated by the Prospectus or pursuant to the terms of
     its outstanding securities or a bona fide financing transaction.

          (aa) The Company and each of its Subsidiaries has filed all foreign,
     federal, state and local income tax returns that are required to be filed
     or has requested extensions thereof (except in any case in which the
     failure so to file would not have a Material Adverse Effect) and has paid
     all taxes required to be paid by it and any other assessment, fine or
     penalty levied against it, to the extent that any of the foregoing is due
     and payable, except for any such tax, assessment, fine or penalty that is
     currently being contested in good faith or as described in or contemplated
     by the Prospectus or which would not result in a Material Adverse Effect.

          (bb) Commencing with the Company's taxable year ended December 31,
     1994, the Company was organized and has operated in conformity with the
     requirements for qualification and taxation as a real estate investment
     trust ("REIT") under Sections 856 through 860 of the Internal Revenue Code
     of 1986, as amended (the "CODE"), and its proposed method of operations
     will enable it to continue to meet the requirements for qualification and
     taxation as a REIT. All statements in the Prospectus regarding the
     Company's qualification as a REIT are true, complete and correct in all
     material respects.

          (cc) Each certificate signed by any officer or authorized
     representative of the Company or any Subsidiary and delivered to the
     Representatives or counsel for the Underwriters shall be deemed to be a
     representation and warranty by the Company or any Subsidiary to each
     Underwriter as to the matters covered thereby.

          (dd) Except for the shares of capital stock or other equity interests
     of each of the Subsidiaries owned by the Company and such Subsidiaries,
     neither the Company nor any such Subsidiary owns any shares of stock or any
     other equity securities of any corporation or has any equity interest in
     any firm, partnership, association or other entity, except as described in
     or contemplated by the Prospectus.

          (ee) The Company and each of its Subsidiaries maintain a system of
     internal accounting controls sufficient to provide reasonable assurance
     that (1) transactions are executed in accordance with management's general
     or specific authorizations; (2) transactions are recorded as necessary to
     permit preparation of financial statements in conformity with generally
     accepted


<Page>

     accounting principles and to maintain asset accountability; (3) access to
     assets, financial and corporate books and records is permitted only in
     accordance with management's general or specific authorization; and (4) the
     recorded accountability for assets is compared with the existing assets at
     reasonable intervals and appropriate action is taken with respect to any
     differences.

          (ff) Neither the Company nor any of the Subsidiaries is in breach or
     violation of its respective declaration of trust, charter, bylaws,
     partnership agreement or other organizational document, as the case may be,
     or in default in the performance of any obligation, agreement, covenant or
     condition contained in any indenture, loan agreement, mortgage, bond,
     debenture, note agreement, joint venture or partnership agreement, lease or
     other agreement or instrument that is material to the Company and the
     Subsidiaries, taken as a whole, and to which the Company or any of the
     Subsidiaries is a party or by which the Company or any of the Subsidiaries
     or their respective property is bound (and there is no event which, but for
     the passage of time or the giving of notice, or both, would constitute a
     default under any of foregoing), where such violation or default would have
     a Material Adverse Effect.

          (gg) Since January 1, 1998, the Company has timely filed all documents
     required to be filed by it under the Exchange Act.

          (hh) No relationship, direct or indirect, exists between or among the
     Company or the Subsidiaries on the one hand, and the trustees, directors,
     officers, shareholders, customers or suppliers of the Company or the
     Subsidiaries on the other hand, which is required by the Act or the rules
     of the NASD to be described in the Registration Statement and the
     Prospectus which is not so described.

          (ii) There are no contracts, agreements, letters of intent,
     understandings or any other documents relating to the pending acquisition
     of any real property by the Company or the Operating Partnership that are
     required to be disclosed in the Prospectus and that are not so disclosed.

     3.   PURCHASE, SALE AND DELIVERY OF OFFERED SECURITIES. On the basis of the
representations, warranties and agreements herein contained, but subject to the
terms and conditions herein set forth, the Company agrees to sell to the
Underwriters, and the Underwriters agree, severally and not jointly, to purchase
from the Company, at a purchase price of $24.0625 per share, the respective
numbers of shares of Firm Securities set forth opposite the names of the
Underwriters in Schedule I hereto. In order to meet the requirements for listing
the Offered Securities on the NYSE, the Underwriters undertake to sell (i) the
Offered Securities to ensure a minimum of 100 beneficial holders with a minimum
of 100,000 Offered Securities outstanding and (ii) sufficient Offered Securities
so that following the offering of the Offered Securities, the Offered Securities
have a minimum aggregate market value of at least $2.0 million.

     The Company will deliver the Firm Securities, with transfer taxes thereon
duly paid, to the Representatives in book entry form through the facilities of
The Depository Trust Company ("DTC") for the respective accounts of the
Underwriters against payment of the purchase price in Federal (same day) funds
by wire transfer to an account of the Company at First Union Bank in Baltimore,
Maryland, in connection with the closing of such transactions, at the office of
Morgan, Lewis & Bockius LLP, Philadelphia, Pennsylvania, at 10:00 A.M., New York
time, on September 13, 2001, or at such other time not later than seven full
business days thereafter as Credit Suisse First Boston Corporation ("CSFBC") and
the Company determine, such time being herein referred to as the "FIRST CLOSING
DATE". For purposes of Rule 15c6-1 under the Exchange Act, the First Closing
Date (if later than the otherwise applicable settlement date) shall be the
settlement date for payment of funds and delivery of securities for all the
Offered Securities sold pursuant to the offering. Prior to the First Closing
Date, the Company will also deliver the form of fully registered global
certificate that will be deposited with DTC for the Firm Securities that the
several Underwriters have agreed to purchase hereunder.


<Page>

     In addition, upon written notice from CSFBC given to the Company from time
to time not more than 30 days subsequent to the date of the Prospectus (or, if
such 30th day shall be a Saturday or Sunday or a holiday, on the next business
day thereafter when the NYSE is open for trading), the Underwriters may purchase
all or less than all of the Optional Securities at the per share purchase price
(including any accumulated dividends thereon to the related Optional Closing
Date (as hereinafter defined)) to be paid for the Firm Securities. The
Underwriters shall not be under any obligation to purchase any of the Optional
Securities prior to the exercise of such option. The Company agrees to sell to
the Underwriters the number of shares of Optional Securities specified in such
notice and the Underwriters agree, severally and not jointly, to purchase such
Optional Securities. Such Optional Securities shall be purchased for the account
of each Underwriter in the same proportion as the number of shares of Firm
Securities set forth opposite such Underwriter's name bears to the total number
of shares of Firm Securities (subject to adjustment by CSFBC to eliminate
fractions) and may be purchased by the Underwriters only for the purpose of
covering over-allotments made in connection with the sale of the Firm
Securities. No Optional Securities shall be sold or delivered unless the Firm
Securities previously have been, or simultaneously are, sold and delivered. The
right to purchase the Optional Securities or any portion thereof may be
exercised from time to time and to the extent not previously exercised may be
surrendered and terminated at any time upon notice by CSFBC to the Company.

     Each time for the delivery of and payment for the Optional Securities,
being herein referred to as an "OPTIONAL CLOSING DATE," which may be the First
Closing Date (the First Closing Date and each Optional Closing Date, if any,
being sometimes referred to as a "CLOSING DATE"), shall be determined by CSFBC
but shall be not later than five (5) full business days after written notice of
election to purchase Optional Securities is given. The Company will deliver the
Optional Securities being purchased, with transfer taxes thereon duly paid, to
the Representatives in book entry form through the facilities of the DTC on each
Optional Closing Date for the accounts of the several Underwriters against
payment of the purchase price in Federal (same day) funds by wire transfer to an
account of the Company, in connection with the closing of the transactions, at
the above office. Prior to each Optional Closing Date, the Company will also
deliver the form of fully registered global certificate that will be deposited
with DTC for the Optional Securities that the several Underwriters have agreed
to purchase hereunder.

     4.   OFFERING BY UNDERWRITERS. It is understood that the several
Underwriters propose to offer the Offered Securities for sale to the public as
set forth in the Prospectus.

     5.   CERTAIN AGREEMENTS OF THE COMPANY AND THE OPERATING PARTNERSHIP. The
Company and the Operating Partnership agree with the several Underwriters that:

          (a)  The Company will file the final Prospectus with the Commission
     pursuant to and in accordance with subparagraph (5) of Rule 424(b) not
     later than the second business day following the execution and delivery of
     this Agreement). The Company will advise CSFBC promptly of any such filing
     pursuant to Rule 424(b).

          (b)  The Company will advise CSFBC promptly of any proposal to amend
     or supplement the Registration Statement as filed or the related Prospectus
     and will not effect such amendment or supplementation without CSFBC's
     consent which shall not be unreasonably withheld. The Company will prepare
     and file with the Commission, in accordance with the rules and regulations
     of the Commission, promptly upon request by the Representatives or counsel
     for the Underwriters, any amendments to the Registration Statement or
     amendments or supplements to the Prospectus that may be necessary or
     advisable in connection with the distribution of the Offered Securities by
     the several Underwriters, and will use its best efforts to cause any such
     amendment to the Registration Statement to be declared effective by the
     Commission as promptly as possible. The Company will also advise CSFBC
     promptly of the effectiveness of the Registration Statement (if its
     Effective Time is subsequent to the execution and delivery of this
     Agreement) and of any amendment or supplementation of the Registration
     Statement or the


<Page>

     Prospectus and of the institution by the Commission of any stop order
     proceedings in respect of the Registration Statement and of the suspension
     of the qualification of the Offered Securities for offering or sale in any
     jurisdiction and will use its best efforts to prevent the issuance of any
     such stop order and to obtain as soon as possible its lifting, if issued.

          (c)  The Company will advise CSFBC, promptly after receiving notice or
     obtaining knowledge thereof and, if requested by the Underwriters, to
     confirm such advice in writing, of (i) the issuance by the Commission of
     any stop order suspending the effectiveness of the Registration Statement
     or any Registration Statement filed under Rule 462(b) ("RULE 462(b)") under
     the Act or any post-effective amendment thereto or any order directed at
     any document incorporated by reference in the Registration Statement or the
     Prospectus or any amendment or supplement thereto or any order preventing
     or suspending the use of any Prospectus or any amendment or supplement
     thereto, (ii) the suspension of the qualification of the Offered Securities
     for offering or sale in any jurisdiction, (iii) the institution,
     threatening or contemplation of any proceeding for any such purpose, (iv)
     the effectiveness of any amendment to the Registration Statement or any
     Rule 462(b) Registration Statement, the transmittal to the Commission for
     filing of any Prospectus or other supplement or amendment thereto to be
     filed pursuant to the Act, any request made by the Commission for amending
     the Registration Statement or any Rule 462(b) Registration Statement, for
     amending or supplementing any preliminary prospectus or the Prospectus or
     for additional information or (v) the happening of any event during the
     period referred to in Section 5(d) below which makes any statement of a
     material fact made in the Registration Statement or Prospectus untrue or
     which requires any additions to or changes in the foregoing in order to
     make the statements therein not misleading. The Company will use its best
     efforts to prevent the issuance of any such stop order and, if any such
     stop order is issued, to obtain the withdrawal or lifting thereof as
     promptly as possible.

          (d)  At any time when a prospectus relating to the Offered Securities
     is required to be delivered under the Act in connection with sales by any
     Underwriter or dealer, the Company (i) will comply with all requirements
     imposed upon it by the Act and the Exchange Act to the extent necessary to
     permit the continuance of sales of or dealings in the Offered Securities in
     accordance with the provisions hereof and of the Prospectus, as then
     amended or supplemented, (ii) will not file with the Commission the
     Prospectus, any amendment or supplement thereto or any amendment to the
     Registration Statement or any Rule 462(b) Registration Statement of which
     the Representatives shall not previously have been advised and furnished
     with a copy for a reasonable period of time prior to the proposed filing
     and as to which filing the Representatives shall not have given their
     consent which shall not be unreasonably withheld, and (iii) if any event
     occurs as a result of which the Prospectus as then amended or supplemented
     would include an untrue statement of a material fact or omit to state any
     material fact necessary to make the statements therein, in the light of the
     circumstances under which they were made, not misleading, or if it is
     necessary at any time to amend the Prospectus to comply with the Act, will
     promptly notify CSFBC of such event and will promptly prepare and file with
     the Commission, at its own expense, an amendment or supplement which will
     correct such statement or omission or an amendment which will effect such
     compliance. Neither CSFBC's consent to, nor the Underwriters' delivery of,
     any such amendment or supplement shall constitute a waiver of any of the
     conditions set forth in Section 6.

          (e)  As soon as practicable, but not later than the Availability Date
     (as hereinafter defined), the Company will make generally available to its
     securityholders an earnings statement covering a period of at least 12
     months beginning after the Effective Date of the Initial Registration
     Statement which will satisfy the provisions of Section 11(a) of the Act.
     For the purpose of the preceding sentence, "AVAILABILITY DATE" means the
     45th day after the end of the fourth fiscal quarter following the fiscal
     quarter that includes such Effective Date, except that, if


<Page>

     such fourth fiscal quarter is the last quarter of the Company's fiscal
     year, "AVAILABILITY DATE" means the 90th day after the end of such fourth
     fiscal quarter.

          (f)  The Company will furnish, without charge, to the Representatives
     copies of each Prospectus included in the Registration Statement, and, so
     long as a prospectus relating to the Offered Securities is required to be
     delivered under the Act in connection with sales by any Underwriter or
     dealer, the Prospectus and all amendments and supplements to such documents
     (in each case including exhibits thereto), in each case in such quantities
     as CSFBC requests. The Prospectus shall be so furnished on or prior to 3:00
     P.M., New York time, on the business day following the later of the
     execution and delivery of this Agreement or the Effective Time of the
     Registration Statement. All other documents shall be so furnished as soon
     as available. The Company will pay the expenses of printing and
     distributing to the Underwriters all such documents.

          (g)  The Company will arrange for the registration or qualification of
     the Offered Securities for offering and sale under the applicable state
     securities or blue sky laws and real estate syndication laws of such
     jurisdictions as CSFBC designates and will continue such registration or
     qualifications in effect for as long as may be necessary to complete the
     distribution of the Offered Securities and to file such consents to service
     of process or other documents as may be necessary in order to effect such
     registration or qualification; provided, however, that in connection
     therewith the Company shall not be required to qualify as a foreign
     corporation or to execute a general consent to service of process in any
     jurisdiction.

          (h)  During the period of five years hereafter, the Company will
     furnish to the Representatives and, upon request, to each of the other
     Underwriters, as soon as practicable after the end of each fiscal year, a
     copy of its annual report to shareholders for such year; and the Company
     will furnish to the Representatives (i) as soon as available, a copy of
     each report and any definitive proxy statement of the Company filed with
     the Commission under the Exchange Act or mailed to shareholders, and (ii)
     from time to time, such other information concerning the Company as CSFBC
     may reasonably request.

          (i)  The Company will pay all costs, fees, taxes and expenses incident
     to the performance of its obligations under this Agreement, whether or not
     the transactions contemplated herein are consummated or this Agreement is
     terminated, including all costs, fees, taxes and expenses incident to (i)
     the printing, filing or other production of documents with respect to the
     transactions, including any costs of printing the Registration Statement
     originally filed with respect to the Offered Securities and any amendment
     thereto, any Rule 462(b) Registration Statement and the Prospectus and any
     amendment or supplement thereto, this Agreement and any blue sky memoranda,
     (ii) all arrangements relating to the mailing and delivery to the
     Underwriters of copies of the foregoing documents, (iii) the fees, expenses
     and disbursements of the counsel, accountants and any other experts or
     advisors retained by the Company, (iv) preparation, printing, issuance and
     delivery to the Underwriters of any certificates evidencing the Offered
     Securities, including transfer agent's and registrar's fees, (v) the filing
     of the Articles Supplementary with the SDAT and the registration or
     qualification of the Offered Securities under state securities and blue sky
     laws and the real estate syndication laws of the several states, including
     filing fees and fees and disbursements of counsel for the Underwriters
     relating thereto, (vi) the filing fees and disbursement of counsel for the
     Underwriters solely in connection with the review and clearance of the
     offering of the Offered Securities by the Commission (and the NASD)
     relating to the Offered Securities, (vii) the listing of the Offered
     Securities on the NYSE, (viii) meetings with prospective investors in the
     Offered Securities (other than shall have been specifically approved by the
     Representatives to be paid for by the Underwriters), (ix) advertising
     approved by the Company relating to the offering of the Offered Securities
     (other than shall have been specifically approved by the Representatives to
     be paid for


<Page>

     by the Underwriters) and (x) any transfer taxes imposed on the sale by the
     Company of the Offered Securities to the Underwriters. If the sale of the
     Offered Securities provided for herein is not consummated because any
     condition to the obligations of the Underwriters set forth in Section 6
     hereof is not satisfied, because this Agreement is terminated or because of
     any failure, refusal or inability on the part of the Company or the
     Operating Partnership to perform all obligations and satisfy all conditions
     on its part to be performed or satisfied hereunder other than by reason of
     a default by any of the Underwriters, the Company and the Operating
     Partnership will reimburse the Underwriters severally upon demand for all
     out-of-pocket expenses (including fees and disbursements of counsel) that
     are the responsibility of the Company pursuant to this Section 5(i) and
     that shall have been incurred by them in connection with the proposed
     purchase and sale of the Offered Securities. The Company and the Operating
     Partnership shall not in any event be liable to any of the Underwriters for
     the loss of anticipated profits from the transactions covered by this
     Agreement.

          (j)  The Company will apply the net proceeds from the sale of the
     Offered Securities as set forth under "Use of Proceeds" in the Prospectus.

          (k)  The Company will not, at any time, directly or indirectly, (i)
     take any action designed to cause or to result in, or that has constituted
     or which might reasonably be expected to constitute, the stabilization or
     manipulation of the price of any security of the Company to facilitate the
     sale or resale of the Offered Securities or (ii) (A) sell, bid for,
     purchase, or pay anyone any compensation for soliciting purchases of, the
     Offered Securities or (B) pay or agree to pay to any person any
     compensation for soliciting another to purchase any other securities of the
     Company.

          (l)  If at any time during the first to conclude of the 25-day period
     after the Registration Statement becomes effective or the period prior to
     the Optional Closing Date, any rumor, publication or event relating to or
     affecting the Company shall occur as a result of which in your opinion the
     market price of the Offered Securities has been or is likely to be
     materially affected (regardless of whether such rumor, publication or event
     necessitates a supplement to or amendment of the Prospectus), the Company
     will, after notice from you advising the Company to the effect set forth
     above, forthwith prepare, consult with you concerning the substance of, and
     disseminate a press release or other public statement, reasonably
     satisfactory to you, responding to or commenting on such rumor, publication
     or event.

          (m)  If the Company elects to rely on Rule 462(b), the Company shall
     both file a Rule 462(b) Registration Statement with the Commission in
     compliance with Rule 462(b) and pay the applicable fees or give irrevocable
     instructions for the payment of such fees in accordance with Rule 111
     promulgated under the Act by the earlier of (i) 10:00 A.M. Eastern time on
     the date following the date of this Agreement and (ii) the time
     confirmations are sent or given, as specified by Rule 462(b)(2).

          (n)  The Company will use its best efforts to cause the Offered
     Securities to be duly authorized for listing by the NYSE prior to the First
     Closing Date and to maintain the listing of the Offered Securities on the
     NYSE for a period of two years after the First Closing Date and thereafter
     unless the Company's Board of Trustees determines that it is no longer in
     the best interests of the Company for the Offered Securities to continue to
     be so listed.

          (o)  During the period when the Prospectus is required to be delivered
     under the Act or the Exchange Act in connection with sales of the Offered
     Securities, to file all documents required to be filed by it with the
     Commission pursuant to Section 13, 14 or 15 of the Exchange Act within the
     time periods required by the Exchange Act.


<Page>

          (p)  To use its best efforts to do and perform all things required to
     be done and performed under this Agreement by the Company or the Operating
     Partnership prior to the First Closing Date and Optional Closing Date, as
     the case may be, and to satisfy all conditions precedent to the delivery of
     the Offered Securities.

          (q)  The Company will use its best efforts to continue to qualify as a
     REIT under Sections 856 through 860 of the Code unless the Company's Board
     of Trustees determines that it is no longer in the best interests of the
     Company to be so qualified.

          (r)  The Company shall duly file the Articles Supplementary
     designating the Preferred Shares with the SDAT.

     6.   CONDITIONS OF THE OBLIGATIONS OF THE UNDERWRITERS. The obligations
of the several Underwriters to purchase and pay for the Firm Securities under
this Agreement shall be subject, in the Representatives' sole discretion, to the
satisfaction of each of the following conditions:

          (a)  All the representations and warranties of the Company and the
     Operating Partnership contained in this Agreement and all statements of
     officers of the Company and Operating Partnership made pursuant to this
     Agreement shall be true and correct, in all material respects, on the First
     Closing Date with the same force and effect as if made on and as of the
     First Closing Date.

          (b)  The Registration Statement, including any Rule 462(b)
     Registration Statement, has become effective under the Act; the Prospectus,
     as the case may be, and any amendment or supplement thereto, shall have
     been filed with the Commission pursuant to Rule 424(b) within the
     applicable time period prescribed for such filing by such Rule; if the
     Company is required to file a Rule 462(b) Registration Statement after the
     effectiveness of this Agreement, such Rule 462(b) Registration Statement
     shall have been filed by 10:00 A.M., New York City time, on the day after
     the date of this Agreement; and no stop order suspending the effectiveness
     of the Registration Statement or any post-effective amendment thereto and
     no order directed at any document incorporated by reference in the
     Registration Statement or the Prospectus or any amendment or supplement
     thereto shall have been issued, and no proceedings for that purpose shall
     have been instituted or threatened, or, to the knowledge of the Company,
     after due inquiry, shall be contemplated by the Commission. No stop order
     suspending the effectiveness of the Registration Statement or any
     post-effective amendment thereto and no order directed at any document
     incorporated by reference in the Registration Statement or the Prospectus
     or any amendment or supplement thereto shall have been issued, and no
     proceedings for that purpose shall have been instituted or threatened, or,
     to the knowledge of the Company, after due inquiry, shall be contemplated
     by the state securities authority of any jurisdiction.

          (c)  Subsequent to the execution and delivery of this Agreement, there
     shall not have occurred (i) any change, or any development or event
     involving a prospective change, in the condition (financial or other),
     business, properties or results of operations of the Company and its
     Subsidiaries taken as one enterprise which, in the judgment of a majority
     in interest of the Underwriters including the Representatives, is material
     and adverse and makes it impractical or inadvisable to proceed with
     completion of the public offering or the sale of and payment for the
     Offered Securities; (ii) any downgrading in the rating of any debt
     securities or preferred stock of the Company by any "nationally recognized
     statistical rating organization" (as defined for purposes of Rule 436(g)
     under the Act), or any public announcement that any such organization has
     under surveillance or review its rating of any debt securities or preferred
     stock of the Company (other than an announcement with positive implications
     of a possible upgrading, and no implication of a possible downgrading, of
     such rating) or any announcement that the Company has been placed on
     negative outlook; (iii) any material suspension or material limitation of


<Page>

     trading in securities generally on the NYSE, or any setting of minimum
     prices for trading on such exchange, or any suspension of trading of any
     securities of the Company on any exchange or in the over-the-counter
     market; (iv) any banking moratorium declared by U.S. Federal or New York
     authorities; or (v) any outbreak or escalation of major hostilities in
     which the United States is involved, any declaration of war by Congress or
     any other substantial national or international calamity or emergency if,
     in the judgment of a majority in interest of the Underwriters including the
     Representatives, the effect of any such outbreak, escalation, declaration,
     calamity or emergency makes it impractical or inadvisable to proceed with
     completion of the public offering or the sale of and payment for the
     Offered Securities.

          (d)  The Representatives shall have received an opinion, dated the
     First Closing Date, of Morgan, Lewis & Bockius LLP, counsel for the
     Company, to the effect that:

               (i)  The Company and each of the Subsidiaries are validly
          existing as corporations, limited partnerships or real estate
          investment trusts or limited liability companies, as the case may be
          in good standing under the laws of their respective jurisdictions of
          formation and are duly qualified and registered to transact business
          as foreign corporations, limited partnerships or real estate
          investment trusts or limited liability companies, as the case may be
          and are in good standing under the laws of the respective
          jurisdictions identified on Schedule II hereto where the ownership or
          leasing of their respective properties or the conduct of their
          respective businesses requires such qualification, except where the
          failure to be so qualified would not have a Material Adverse Effect;

               (ii) The Company and each of the Subsidiaries have trust or
          partnership authority or power, whichever is appropriate, to own,
          operate or lease their respective properties and other assets and
          conduct the respective businesses in which they are engaged or propose
          to engage, in each case, as described in the Registration Statement
          and the Prospectus, and the Company and the Operating Partnership have
          trust or partnership power, as the case may be, to enter into this
          Agreement and to carry out all the terms and provisions hereof to be
          carried out by them;

               (iii) The Company has an authorized capitalization consisting of
          50,000,000 shares of beneficial interest as set forth in the
          Prospectus; the Offered Securities have been duly authorized for
          issuance and sale to the Underwriters pursuant to this Agreement by
          all necessary action of the Company and, when validly issued and
          delivered to and paid for by the Underwriters pursuant to this
          Agreement and in accordance with the resolutions of the Board of
          Trustees of the Company authorizing their issuance, will be duly
          authorized, validly issued, fully paid and nonassessable; no holders
          of outstanding shares of beneficial interest of the Company are
          entitled, to such counsel's knowledge, to any preemptive or other
          rights to subscribe for any of the Offered Securities; the terms of
          the Offered Securities conform in all material respects to all
          statements and descriptions related thereto under the captions
          "Description of Shares" and "Description of Series F Preferred Shares"
          contained in the Prospectus. The form of share certificate evidencing
          the Offered Securities is in due and proper form in all material
          respects and complies in all material respects with all applicable
          legal requirements under Maryland law. The issuance of the Offered
          Securities is not subject to any preemptive or other similar rights
          arising under Title 8 of the Corporations and Associations Article of
          the Annotated Code of Maryland or the Company's declaration of trust
          or bylaws, as amended to date;

               (iv) The statements set forth under the heading "Description of
          Series F Preferred Shares" in the Prospectus, insofar as such
          statements purport to summarize


<Page>

          certain provisions of the Offered Securities and charter documents of
          the Company and the Operating Partnership, have been reviewed by such
          counsel and are correct in all material respects and provide a fair
          summary of such provisions; and the statements set forth under the
          heading "Certain Federal Income Tax Matters" and "Description of
          Series F Preferred Shares" in the Prospectus, insofar as such
          statements constitute statements of law, description of statutes,
          rules or regulations, a summary of the legal matters or proposed
          legislation referred to therein, have been reviewed by such counsel
          and are correct in all material respects and provide a fair summary of
          such matters;

               (v)  The execution and delivery of this Agreement has been duly
          authorized by all necessary action of the Company and the Operating
          Partnership, and this Agreement has been duly executed and delivered
          by the Company and the Operating Partnership;

               (vi) The filing of the Articles Supplementary with the SDAT has
          been duly authorized by all necessary action of the Company, and the
          Articles Supplementary are in full force and effect subject to (a) the
          effect of bankruptcy, insolvency, fraudulent conveyance,
          reorganization, moratorium or other similar laws now or hereafter in
          effect relating to or affecting the rights and remedies of creditors
          and (b) the effect of general principles of equity, whether
          enforcement is considered in a proceeding in equity or at law, and the
          discretion of the court before which any proceeding therefor may be
          brought;

               (vii) To such counsel's knowledge, no legal or governmental
          proceedings are pending to which the Company or any of the
          Subsidiaries is a party or to which the property of the Company or any
          of the Subsidiaries is subject that are required to be described in
          the Registration Statement or the Prospectus and are not described
          therein, and, to the extent described therein, the descriptions
          thereof are accurate in all material respects and, to the knowledge of
          such counsel, no such proceedings have been threatened against the
          Company or any of the Subsidiaries or with respect to any of their
          respective properties; and to such counsel's knowledge no contract,
          statute, regulation or other document is required to be described in
          the Registration Statement or the Prospectus or to be filed as an
          exhibit to the Registration Statement that is not described therein or
          filed as an exhibit thereto;

               (viii) To such counsel's knowledge, the issuance, offering and
          sale of the Offered Securities to the Underwriters by the Company
          pursuant to this Agreement, the execution, delivery and performance
          and the compliance with this Agreement by the Company and the
          Operating Partnership and the consummation by the Company and the
          Operating Partnership of the other transactions herein contemplated do
          not and will not (A) require the consent, approval, authorization,
          registration, order, filing or qualification of or with any court,
          regulatory body, administrative agency or other governmental
          authority, except such as have been obtained and such as may be
          required under state securities or blue sky laws or real estate
          syndication laws of the various states in connection with the purchase
          and distribution of the securities by the Underwriters, or as may be
          required under the Act or other securities laws OR BYLAWS AND RULES OF
          THE NASD, or the listing requirements of the NYSE or such as have been
          received prior to the date of the opinion, or (B) conflict with or
          result in a breach or violation of any of the terms and provisions of,
          or constitute a default under whether with or without the giving of
          notice or passage of time or both, (x) the declaration of trust and
          bylaws of the Company, the charter and bylaws of each Subsidiary that
          is a corporation, the partnership agreement of each Subsidiary that is
          a partnership or the operating agreement of each Subsidiary that is a
          limited liability company, (y) any document (as in effect on the date
          of such


<Page>

          opinion) listed on Schedule III (it being understood that such counsel
          may assume compliance with the financial covenants contained in any
          such document), (C) violate or conflict with any applicable law, rule
          or administrative regulation of the United States, the State of
          Delaware or the State of Maryland, or (D) violate any order or
          administrative or court decree of which such counsel is aware, except
          in each case (other than for Sections 6(d)(viii)(B)(x) and
          6(d)(viii)(B)(y) above) for requirements, conflicts, breaches,
          violations or defaults that in the aggregate would not have a Material
          Adverse Effect;

               (ix) The Registration Statement is effective under the Act; the
          Prospectus has been filed with the Commission in the manner and within
          the time period required by Rule 424(b) under the Act; and no stop
          order suspending the effectiveness of the Registration Statement or
          any post-effective amendment thereto has been issued, and no
          proceedings for that purpose have been instituted or, to the knowledge
          of such counsel, are threatened or contemplated by the Commission;

               (x)  The documents filed pursuant to the Exchange Act and
          incorporated by reference in the Prospectus (other than the financial
          statements and related schedules, other financial information and
          statistical data derived from such financial statements, schedules and
          other financial data contained therein, as to which counsel need
          express no opinion), when they were filed with the Commission,
          complied as to form in all material respects with the applicable
          requirements of the Exchange Act;

               (xi) The Registration Statement, any Rule 462(b) Registration
          Statement, the Prospectus and each amendment and supplement thereto,
          as of their respective effective and issue dates (in each case,
          including the documents incorporated by reference therein but not
          including the financial statements and related schedules, other
          financial information and statistical data derived from such financial
          statements, schedules and other financial data contained therein, as
          to which such counsel need express no opinion) complied as to form in
          all material respects with the applicable requirements of the Act;

               (xii) The authorized shares of beneficial interest of the Company
          conform as to legal matters in all material respects to the
          description thereof contained in the Prospectus;

               (xiii) The Company and the Subsidiaries are not and, after giving
          effect to the offering and sale of the Offered Securities and the
          application of the proceeds thereof as described in the Prospectus,
          will not be required to be registered as an "investment company" under
          the Investment Company Act of 1940, as amended; and

               (xiv) To such counsel's knowledge, there are no contracts or
          agreements between the Company and any person granting such person the
          right to require the Company to include securities of the Company held
          by such person with the Offered Securities registered pursuant to the
          Registration Statement.

          In addition, Morgan, Lewis & Bockius LLP shall confirm that the
     opinion filed as Exhibit 8.1 to the Registration Statement is true and
     correct as of the date thereof and permit the Underwriters to rely on such
     opinion as if it were addressed to the Underwriters. Also, if the NYSE has
     approved and authorized the listing of the Offered Securities as of the
     Closing Date, Morgan, Lewis & Bockius LLP shall confirm that the Offered
     Securities have been duly authorized for listing, subject to official
     notice of issuance, on the NYSE.

          Further, Morgan, Lewis & Bockius LLP shall state that they have
     participated in conferences with officers and other representatives of the
     Company and the Subsidiaries,


<Page>

     representatives of the independent public accountants for the Company and
     representatives of the Underwriters and their counsel at which the contents
     of the Registration Statement and the Prospectus and related matters were
     discussed. On the basis thereof (relying as to materiality to the extent it
     deems appropriate upon the opinions of officers and other representatives
     of the Company), but without independent verification by such counsel of,
     and without passing upon or assuming any responsibility for, the accuracy,
     completeness or fairness of the statements contained in the Registration
     Statement or the Prospectus or any amendments or supplements thereto, no
     facts have come to the attention of such counsel that lead them to believe
     that (i) the Registration Statement, at the time such Registration
     Statement became effective, contained any untrue statement of a material
     fact or omitted to state any material fact required to be stated therein or
     necessary in order to make the statements therein not misleading or (ii)
     the Prospectus, as of its date or at the First Closing Date contained or
     contains any untrue statement of a material fact or omitted or omits to
     state a material fact necessary to make the statements therein, in the
     light of the circumstances under which they were made, not misleading (it
     being understood that such counsel need express no opinion with respect to
     the financial statements and related schedules and other financial and
     statistical data derived from such financial statements included in the
     Registration Statement or the Prospectus).

          In giving its opinion, such counsel shall expressly limit their
     opinion to matters of Federal and Pennsylvania law and the Revised Uniform
     Limited Partnership Act of the State of Delaware, the General Corporation
     Law of the State of Delaware and Title 8 of the Corporations and
     Associations Article of the Annotated Code of Maryland and may rely without
     independent verification (A) as to all matters of fact, upon certificates
     and statements of officers, trustees, directors, partners and employees of
     and accountants for the Company and the Subsidiaries and (B) as to the good
     standing and qualification of the Company and the Subsidiaries to do
     business in any state or jurisdiction, upon certificates of appropriate
     government officials or opinions of counsel in such jurisdictions. Counsel
     need express no opinion (i) as to the enforceability of forum selection
     clauses or (ii) with respect to the requirements of, or compliance with,
     any state securities or blue sky or real estate syndication laws.

          For the purposes of the opinions presented in this Section 6(d), the
     term "Subsidiaries" shall include only those subsidiaries that are listed
     on Schedule IV. References to the Registration Statement and the Prospectus
     in this paragraph (d) shall include any amendment or supplement thereto at
     the date of such opinion.

          (e)  You shall have received on the First Closing Date an opinion or
     opinions (satisfactory to you and your counsel), dated the First Closing
     Date, of John H. Gurley, Esq., General Counsel to the Company, as to the
     following matters:

               (i)  The Company and each of the Subsidiaries are validly
          existing as corporations, limited partnerships or real estate
          investment trusts or limited liability companies, as the case may be
          in good standing under the laws of their respective jurisdictions of
          formation and are duly qualified and registered to transact business
          as foreign corporations, limited partnerships or real estate
          investment trusts or limited liability companies, as the case may be
          and are in good standing under the laws of the respective
          jurisdictions identified on Schedule II hereto where the ownership or
          leasing of their respective properties or the conduct of their
          respective businesses requires such qualification, except where the
          failure to be so qualified would not have a Material Adverse Effect;

               (ii) The Company and each of the Subsidiaries have trust or
          partnership authority or power, whichever is appropriate, to own,
          operate or lease their respective properties and other assets and
          conduct the respective businesses in which they are


<Page>

          engaged or propose to engage, in each case, as described in the
          Registration Statement and the Prospectus, and the Company and the
          Operating Partnership have trust or partnership power, as the case may
          be, to enter into this Agreement and to carry out all the terms and
          provisions hereof to be carried out by them;

               (iii) The issued and outstanding common and preferred units of
          limited partnership of the Operating Partnership, and the issued and
          outstanding membership interests and other equity interests, as the
          case may be, of each of the other Subsidiaries have been duly
          authorized and validly issued, are with respect to corporate
          Subsidiaries fully paid and nonassessable, have been issued in
          compliance with all applicable federal and state securities laws and,
          to the knowledge of such counsel, were not issued in violation of or
          subject to any preemptive rights or other rights to subscribe for or
          purchase securities and, except as otherwise set forth in the
          Prospectus, to the knowledge of such counsel, are owned beneficially
          by the Company free and clear of any perfected security interests or,
          any other security interests, liens, encumbrances, equities or claims,
          except for security interests, liens, encumbrances, equities or claims
          pursuant to the terms of a bona fide financing transaction;

               (iv) To such counsel's knowledge, no legal or governmental
          proceedings are pending to which the Company or any of the
          Subsidiaries is a party or to which the property of the Company or any
          of the Subsidiaries is subject that are required to be described in
          the Registration Statement or the Prospectus and are not described
          therein, and the descriptions thereof are accurate in all material
          respects and, to the knowledge of such counsel, no such proceedings
          have been threatened against the Company or any of the Subsidiaries or
          with respect to any of their respective properties; and to such
          counsel's knowledge no contract, statutes, regulations or other
          document is required to be described in the Registration Statement or
          the Prospectus or to be filed as an exhibit to the Registration
          Statement that is not described therein or filed as required and the
          descriptions of any such contracts, statutes, regulations or other
          documents are accurate in all material respects;

               (v)  To such counsel's knowledge, the issuance, offering and sale
          of the Offered Securities to the Underwriters by the Company pursuant
          to this Agreement, the execution, delivery and performance and the
          compliance with this Agreement by the Company and the Operating
          Partnership and the consummation by the Company and the Operating
          Partnership of the other transactions herein contemplated do not and
          will not (A) require the consent, approval, authorization,
          registration, order, filing or qualification of or with any court,
          regulatory body, administrative agency or other governmental
          authority, except such as have been obtained and such as may be
          required under state securities or blue sky laws or real estate
          syndication laws of the various states in connection with the purchase
          and distribution of the securities by the Underwriters, or as may be
          required under the Act or other securities laws OR BYLAWS AND RULES OF
          THE NASD, or the listing requirements of the NYSE or such as have been
          received prior to the date of the opinion, or (B) conflict with or
          result in a breach or violation of any of the terms and provisions of,
          or constitute a default under whether with or without the giving of
          notice or passage of time or both, (x) the declaration of trust and
          bylaws of the Company, the charter and bylaws of each Subsidiary that
          is a corporation, the partnership agreement of each Subsidiary that is
          a partnership or the operating agreement of each Subsidiary that is a
          limited liability company, (y) any document (as in effect on the date
          of such opinion) listed on Schedule III (it being understood that such
          counsel may assume compliance with the financial covenants contained
          in any such document), (C) violate or conflict with any applicable
          law, rule or administrative regulation of the United States, the State
          of Delaware or the State of Maryland, or (D) violate any order or
          administrative


<Page>

          or court decree of which such counsel is aware, except in each case
          (other than for Sections 6(d)(viii)(B)(x) and 6(d)(viii)(B)(y) above)
          for requirements, conflicts, breaches, violations or defaults that in
          the aggregate would not have a Material Adverse Effect;

               (vi) To the knowledge of such counsel, neither the Company nor
          any of the Subsidiaries is in violation of its respective charter,
          declaration of trust, bylaws, partnership agreement or other
          organizational document, as the case may be, and, to such counsel's
          knowledge, neither the Company nor any of such Subsidiaries is in
          default in the performance or observance of (and there is no event
          which, but for the passage of time or the giving of notice, or both,
          would constitute a default under any of the foregoing), any
          obligation, agreement, covenant or condition contained in any document
          (as in effect on the date of such opinion) listed on Schedule III to
          which the Company or any of such Subsidiaries is a party or by which
          the Company or any of such Subsidiaries or their respective property
          is bound (it being understood that such counsel may assume compliance
          with the financial covenants contained in any such document), except
          in each case for violations or defaults which in the aggregate are not
          reasonably expected to have a Material Adverse Effect;

               (vii) The Company and the Subsidiaries are not and, after giving
          effect to the offering and sale of the Offered Securities and the
          application of the proceeds thereof as described in the Prospectus,
          will not be required to be registered as an "investment company" under
          the Investment Company Act of 1940, as amended; and

          In addition, John H. Gurley shall make statements similar to those
     contained in the second and third paragraphs following Section 6(d)(xiv)
     hereto and shall be entitled to rely on those persons described in the
     third paragraph following Section 6(d)(xiv) described therein. For the
     purposes of the opinions presented in this Section 6(e), the term
     "Subsidiaries" shall include only those subsidiaries that are listed on
     Schedule V.

          (f)  You shall have received on the First Closing Date an opinion,
     dated the First Closing Date, of Clifford Chance Rogers & Wells LLP,
     counsel for the Underwriters, as to the matters referred to in clauses
     (iii) (with respect to the second and fourth clauses only), (iv) (with
     respect to "Description of Series F Preferred Shares" only), (v) and (xi)
     of Section 6(d) and in addition, Clifford Chance Rogers & Wells LLP shall
     make statements similar to those contained in the second and third
     paragraphs following Section 6(d)(xiv) hereto (with respect to Federal, New
     York, Delaware and Maryland laws only) and shall be entitled to rely on
     those persons described in the third paragraph following Section 6(d)(xiv)
     described therein.

          (g)  You shall have received, on each of the date hereof and the First
     Closing Date, a letter dated the date hereof or the First Closing Date, as
     the case may be, in form and substance satisfactory to you (and your
     counsel), from PricewaterhouseCoopers LLP, independent public accountants,
     confirming that they are independent public accountants with respect to the
     Company and the Subsidiaries as required by the Act and with respect to the
     financial and other statistical and numerical information contained in the
     Registration Statement and containing the information and statements of the
     type ordinarily included in accountants' "comfort letters" to Underwriters
     with respect to the financial statements and certain financial information
     contained in the Registration Statement and the Prospectus.

          At the First Closing Date, PricewaterhouseCoopers LLP shall have
     furnished to the Underwriters a letter, dated the date of its delivery,
     which shall confirm, on the basis of a review in accordance with the
     procedures set forth in the letter from it, that nothing has come to its
     attention during the period from the date of the letter referred to in the
     prior sentence to a date (specified in the letter) not more than five days
     prior to the First Closing Date which would


<Page>

     require any change in its letter dated the date hereof if it were required
     to be dated and delivered at the First Closing Date as the case may be.

          References to the Registration Statement and the Prospectus in this
     paragraph (f) with respect to either letter referred to above shall include
     any amendment or supplement thereto at the date of such letter.

          (h)  The Company and the Subsidiaries shall not have failed on or
     prior to the First Closing Date to perform or comply with any of the
     agreements herein contained and required to be performed or complied with
     by the Company on or prior to the First Closing Date.

          (i)  The Representatives shall have received a certificate, dated the
     First Closing Date, of Clay W. Hamlin, III and Roger A. Waesche, Jr.,
     solely in their capacities as the Chief Executive Officer and Chief
     Financial Officer of the Company to the effect that:

               (i)  All the representations and warranties of the Company in
          this Agreement shall be true and correct, in all material respects, on
          the First Closing Date with the same force and effect as if made on
          and as of the First Closing Date. The Company has complied with all
          agreements and all conditions on its part to be performed or satisfied
          hereunder at or prior to the First Closing Date.

               (ii) The Registration Statement, including any Rule 462(b)
          Registration Statement, has become effective under the Act; the
          Prospectus shall have been filed with the Commission pursuant to Rule
          424(b) within the applicable time period prescribed for such filing by
          such Rule and prior to the time the Prospectus was distributed to any
          Underwriter; no stop order suspending the effectiveness of the
          Registration Statement or any post-effective amendment thereto and no
          order directed at any document incorporated by reference in the
          Registration Statement or the Prospectus or any amendment or
          supplement thereto has been issued, and no proceedings for that
          purpose have been instituted or are pending before, or threatened or,
          to the best of the Company's knowledge, after due inquiry, are
          contemplated by the Commission; no stop order suspending the
          effectiveness of the Registration Statement or any post-effective
          amendment thereto and no order directed at any document incorporated
          by reference in the Registration Statement or the Prospectus or any
          amendment or supplement thereto has been issued, and no proceedings
          for that purpose have been instituted or are pending before, or
          threatened or, to the best of the Company's knowledge, after due
          inquiry, are contemplated by the state securities authority of any
          jurisdiction; and

               (iii) Subsequent to the respective dates as of which information
          is given in the Registration Statement and the Prospectus other than
          as set forth in or contemplated by the Registration Statement and the
          Prospectus (exclusive of any amendments or supplements thereto
          subsequent to the date of this Agreement) and prior to the First
          Closing Date, except for changes of a general nature applicable to all
          real estate investment trusts, (i) there has not occurred any material
          adverse change or, to the best knowledge of such persons, any
          development involving a prospective material adverse change in the
          condition, financial or otherwise, or the results of operations,
          business, prospects, management or operations of the Company and the
          Subsidiaries, taken as a whole, (ii) there has been no casualty loss
          or condemnation or other adverse event with respect to any of the
          properties which would be material to the Company or the Subsidiaries,
          (iii) there has not been any material adverse change or any
          development involving a prospective material adverse change in the
          capitalization, long-term or short-term debt or in the shares of
          beneficial interest or equity of the Company or any of the
          Subsidiaries, (iv) except as described in the Prospectus, neither the
          Company nor any of


<Page>

          the Subsidiaries has incurred any material liability or obligation,
          direct or contingent, which would be material, nor have they entered
          into any transactions, other than pursuant to this Agreement and the
          transactions referred to herein or as contemplated in the Prospectus,
          which would be material, to the Company and its Subsidiaries taken as
          a whole, and (v) except for regular quarterly distributions on the
          Offered Securities, the Company has not paid or declared and will not
          pay or declare any dividends or other distributions of any kind on any
          class of its shares of beneficial interest except in the ordinary
          course of business consistent with such practice.

          (j)  On or before the First Closing Date, the Representatives and
     counsel for the Underwriters shall have received such further certificates,
     letters, documents, opinions or other information as they may have
     reasonably requested from the Company for the purpose of enabling them to
     pass upon the issuance and sale of the Offered Securities, as herein
     contemplated and related proceedings, or in order to evidence the accuracy
     of any of the representations or warranties, or the fulfillment of any of
     the conditions, herein contained; and all proceedings taken by the Company
     in connection with the issuance and sale of the Offered Securities as
     herein contemplated shall be reasonably satisfactory in form and substance
     to the Representatives and counsel for the Underwriters.

          (k)  The Offered Securities shall have been approved for listing on
     the NYSE, subject to official notice of issuance.

          (l)  The Company shall have duly filed the Articles Supplementary
     designating the Preferred Shares with the SDAT.

     The respective obligations of the several Underwriters to purchase and
pay for any Optional Securities shall be subject, in their discretion, to each
of the foregoing conditions to purchase the Firm Securities (except that all
references to the Firm Securities and the First Closing Date shall be deemed to
refer to such Optional Securities and the related Optional Closing Date,
respectively), including, without limitation:

          (a)  A certificate, dated such Optional Closing Date, of the President
     or a Vice President and the chief financial or chief accounting officer of
     the Company confirming that the certificates delivered at the First Closing
     Date pursuant to Section 6 hereof remain true and correct in all material
     respects as of such Optional Closing Date.

          (b)  An opinion of Morgan, Lewis & Bockius LLP in form and substance
     satisfactory to you and your counsel, dated such Optional Closing Date,
     relating to the Optional Securities to be purchased on such Optional
     Closing Date and otherwise to the same effect as the opinion required by
     Section 6(d) hereof.

          (c)  An opinion of John H. Gurley, Esq. in form and substance
     satisfactory to you and your counsel, dated such Optional Closing Date,
     relating to the Optional Securities to be purchased on such Optional
     Closing Date and otherwise to the same effect as the opinion required by
     Section 6(e) hereof.

          (d)  An opinion of Clifford Chance Rogers & Wells LLP, counsel for the
     Underwriters, dated such Optional Closing Date, relating to the Optional
     Securities to be purchased on such Optional Closing Date and otherwise to
     the same effect as the opinion required by Section 6(f) hereof.

          (e)  A letter from PricewaterhouseCoopers LLP, in form and substance
     satisfactory to you and your counsel and dated such Optional Closing Date,
     substantially the same in form and


<Page>

     substance as the letter furnished to the Underwriters pursuant to Section
     6(g) hereof, dated not more than five days prior to such Optional Closing
     Date.

     7.   INDEMNIFICATION AND CONTRIBUTION. (1) The Company and the Operating
Partnership will indemnify and hold harmless each Underwriter, its partners,
directors and officers and each person, if any, who controls such Underwriter
within the meaning of Section 15 of the Act, against any losses, claims, damages
or liabilities, joint or several, to which such Underwriter may become subject,
under the Act or otherwise, insofar as such losses, claims, damages or
liabilities (or actions in respect thereof) arise out of or are based upon any
untrue statement or alleged untrue statement of any material fact contained in
any Registration Statement, the Prospectus, or any amendment or supplement
thereto, or any related preliminary prospectus, or arise out of or are based
upon the omission or alleged omission to state therein a material fact required
to be stated therein or necessary to make the statements therein not misleading,
or arise out of any untrue statement or alleged untrue statement made by the
Company or the Operating Partnership in Section 2 of this Agreement, or arise
out of any untrue statement or alleged untrue statement of any material fact
contained in any application or other document, or any amendment or supplement
thereto, executed by the Company or the Operating Partnership or based upon
written information furnished by or on behalf of the Company or the Operating
Partnership filed in any jurisdiction in order to qualify the Offered Securities
under the securities or blue sky laws thereof or filed with the Commission or
any securities association or securities exchange, or arise out of any untrue
statement or alleged untrue statement of any material fact contained in any
audio or visual materials prepared by the Company or the Operating Partnership
or based upon written information furnished by or on behalf of the Company or
the Operating Partnership (including, without limitation, slides, videos, films,
tape recordings) used in connection with the marketing of the Offered
Securities, including, without limitation, statements communicated to securities
analysts employed by the Underwriters, and will reimburse each Underwriter for
any legal or other expenses reasonably incurred by such Underwriter in
connection with investigating or defending any such loss, claim, damage,
liability or action as such expenses are incurred; provided, however, that the
Company will not be liable in any such case to the extent that any such loss,
claim, damage or liability arises out of or is based upon an untrue statement or
alleged untrue statement in or omission or alleged omission from any of such
documents in reliance upon and in conformity with written information furnished
to the Company by any Underwriter through the Representatives specifically for
use therein, it being understood and agreed that the only such information
furnished by any Underwriter consists of the information described as such in
subsection (b) below.

     (a)  Each Underwriter will severally and not jointly indemnify and hold
harmless the Company, its directors and officers and each person, if any who
controls the Company within the meaning of Section 15 of the Act, against any
losses, claims, damages or liabilities to which the Company may become subject,
under the Act or otherwise, insofar as such losses, claims, damages or
liabilities (or actions in respect thereof) arise out of or are based upon any
untrue statement or alleged untrue statement of any material fact contained in
any Registration Statement, the Prospectus, or any amendment or supplement
thereto, or any related preliminary prospectus, or arise out of or are based
upon the omission or the alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, in each case to the extent, but only to the extent, that such untrue
statement or alleged untrue statement or omission or alleged omission was made
in reliance upon and in conformity with written information furnished to the
Company by such Underwriter through the Representatives specifically for use
therein, and will reimburse any legal or other expenses reasonably incurred by
the Company in connection with investigating or defending any such loss, claim,
damage, liability or action as such expenses are incurred, it being understood
and agreed that the only such information furnished by any Underwriter consists
of the following information in the Prospectus furnished on behalf of each
Underwriter: the information in the second and third sentences of the fourth
paragraph under the caption "Underwriting," and the information in the second
and third sentences of the seventh paragraph and the eighth, ninth and tenth
paragraphs under the caption "Underwriting," and the statement regarding the
affiliation of KeyCorp and McDonald Investments, Inc. and the sixth and seventh
sentences in the eleventh paragraph.


<Page>

     (b)  Promptly after receipt by an indemnified party under this Section of
notice of the commencement of any action, such indemnified party will, if a
claim in respect thereof is to be made against the indemnifying party under
subsection (a) or (b) above, notify the indemnifying party of the commencement
thereof; but the omission so to notify the indemnifying party will not relieve
it from any liability which it may have to any indemnified party otherwise than
under subsection (a) or (b) above, except to the extent such omission so to
notify the indemnifying party materially prejudices the indemnifying party. In
case any such action is brought against any indemnified party and it notifies
the indemnifying party of the commencement thereof, the indemnifying party will
be entitled to participate therein and, to the extent that it may wish, jointly
with any other indemnifying party similarly notified, to assume the defense
thereof, with counsel satisfactory to such indemnified party (who shall not,
except with the consent of the indemnified party, be counsel to the indemnifying
party), and after notice from the indemnifying party to such indemnified party
of its election so to assume the defense thereof, the indemnifying party will
not be liable to such indemnified party under this Section for any legal or
other expenses subsequently incurred by such indemnified party in connection
with the defense thereof other than reasonable costs of investigation. No
indemnifying party shall, without the prior written consent of the indemnified
party, effect any settlement of any pending or threatened action in respect of
which any indemnified party is or could have been a party and indemnity could
have been sought hereunder by such indemnified party unless such settlement (i)
includes an unconditional release of such indemnified party from all liability
on any claims that are the subject matter of such action and (ii) does not
include a statement as to, or an admission of, fault, culpability or a failure
to act by or on behalf of an indemnified party.

     (c)  If the indemnification provided for in this Section is unavailable or
insufficient to hold harmless an indemnified party under subsection (a) or (b)
above, then each indemnifying party shall contribute to the amount paid or
payable by such indemnified party as a result of the losses, claims, damages or
liabilities referred to in subsection (a) or (b) above (i) in such proportion as
is appropriate to reflect the relative benefits received by the Company on the
one hand and the Underwriters on the other from the offering of the Offered
Securities or (ii) if the allocation provided by clause (i) above is not
permitted by applicable law, in such proportion as is appropriate to reflect not
only the relative benefits referred to in clause (i) above but also the relative
fault of the Company on the one hand and the Underwriters on the other in
connection with the statements or omissions which resulted in such losses,
claims, damages or liabilities as well as any other relevant equitable
considerations. The relative benefits received by the Company on the one hand
and the Underwriters on the other shall be deemed to be in the same proportion
as the total net proceeds from the offering (before deducting expenses) received
by the Company bear to the total underwriting discounts and commissions received
by the Underwriters. The relative fault shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact or the omission or alleged omission to state a material fact relates to
information supplied by the Company or the Underwriters and the parties'
relative intent, knowledge, access to information and opportunity to correct or
prevent such untrue statement or omission. The amount paid by an indemnified
party as a result of the losses, claims, damages or liabilities referred to in
the first sentence of this subsection (d) shall be deemed to include any legal
or other expenses reasonably incurred by such indemnified party in connection
with investigating or defending any action or claim which is the subject of this
subsection (d). Notwithstanding the provisions of this subsection (d), no
Underwriter shall be required to contribute any amount in excess of the amount
by which the total price at which the Offered Securities underwritten by it and
distributed to the public were offered to the public exceeds the amount of any
damages which such Underwriter has otherwise been required to pay by reason of
such untrue or alleged untrue statement or omission or alleged omission. No
person found by a court to be guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Act) shall be entitled to contribution from any
person who was not found by a court to be guilty of such fraudulent
misrepresentation. The Underwriters' obligations in this subsection (d) to
contribute are several in proportion to their respective underwriting
obligations and not joint.


<Page>

     (d)  The obligations of the Company under this Section shall be in addition
to any liability which the Company may otherwise have and shall extend, upon the
same terms and conditions, to each person, if any, who controls any Underwriter
within the meaning of the Act; and the obligations of the Underwriters under
this Section shall be in addition to any liability which the respective
Underwriters may otherwise have and shall extend, upon the same terms and
conditions, to each director of the Company, to each officer of the Company who
has signed a Registration Statement and to each person, if any, who controls the
Company within the meaning of the Act.

     8.   DEFAULT OF UNDERWRITERS. If any Underwriter or Underwriters default in
their obligations to purchase Offered Securities hereunder on either the First
or any Optional Closing Date and the aggregate number of shares of Offered
Securities that such defaulting Underwriter or Underwriters agreed but failed to
purchase does not exceed 10% of the total number of shares of Offered Securities
that the Underwriters are obligated to purchase on such Closing Date, CSFBC may
make arrangements satisfactory to the Company for the purchase of such Offered
Securities by other persons, including any of the Underwriters, but if no such
arrangements are made by such Closing Date, the non-defaulting Underwriters
shall be obligated severally, in proportion to their respective commitments
hereunder, to purchase the Offered Securities that such defaulting Underwriters
agreed but failed to purchase on such Closing Date. If any Underwriter or
Underwriters so default and the aggregate number of shares of Offered Securities
with respect to which such default or defaults occur exceeds 10% of the total
number of shares of Offered Securities that the Underwriters are obligated to
purchase on such Closing Date and arrangements satisfactory to CSFBC and the
Company for the purchase of such Offered Securities by other persons are not
made within 36 hours after such default, this Agreement will terminate without
liability on the part of any non-defaulting Underwriter or the Company, except
as provided in Section 9 (provided that if such default occurs with respect to
Optional Securities after the First Closing Date, this Agreement will not
terminate as to the Firm Securities or any Optional Securities purchased prior
to such termination). In the event of any default by one or more Underwriters as
described in this Section 8, the Representatives shall have the right to
postpone the First Closing Date or the Optional Closing Date, as the case may
be, established as provided in Section 3 hereof for not more than seven business
days in order that any necessary changes may be made in the arrangements or
documents for the purchase and delivery of the Firm Securities or Optional
Securities, as the case may be. As used in this Agreement, the term
"Underwriter" includes any person substituted for an Underwriter under this
Section. Nothing herein will relieve a defaulting Underwriter from liability for
its default.

     9.   SURVIVAL OF CERTAIN REPRESENTATIONS AND OBLIGATIONS. The respective
indemnities, agreements, representations, warranties and other statements of the
Company or its officers and of the several Underwriters set forth in or made
pursuant to this Agreement will remain in full force and effect, regardless of
any investigation, or statement as to the results thereof, made by or on behalf
of any Underwriter, the Company or any of their respective representatives,
officers or directors or any controlling person, and will survive delivery of
and payment for the Offered Securities. If this Agreement is terminated pursuant
to Section 8 or if for any reason the purchase of the Offered Securities by the
Underwriters is not consummated, the Company shall remain responsible for the
expenses to be paid or reimbursed by it pursuant to Section 5 and the respective
obligations of the Company and the Underwriters pursuant to Section 7 shall
remain in effect, and if any Offered Securities have been purchased hereunder
the representations and warranties in Section 2 and all obligations under
Section 5 shall also remain in effect. If the purchase of the Offered Securities
by the Underwriters is not consummated for any reason other than solely because
of the termination of this Agreement pursuant to Section 8 or the occurrence of
any event specified in clause (iii), (iv) or (v) of Section 6(c), the Company
will reimburse the Underwriters for all out-of-pocket expenses (including fees
and disbursements of counsel) reasonably incurred by them in connection with the
offering of the Offered Securities.

     10.  NOTICES. All communications hereunder will be in writing and, if sent
to the Underwriters, will be mailed, delivered or telegraphed and confirmed to
the Representatives, c/o Credit Suisse First Boston Corporation, Eleven Madison
Avenue, New York, NY 10010-3629,


<Page>

Attention: Transactions Advisory Group, with a copy to Clifford Chance Rogers &
Wells LLP, 200 Park Avenue, New York, NY, 10166, Attention: Robert E. King, Jr.,
or, if sent to the Company, will be mailed, delivered or telegraphed and
confirmed to it at Corporate Office Properties Trust, 401 City Avenue, Suite
615, Bala Cynwyd, PA 19004-1126, Attention: Clay W. Hamlin, III, with a copy to
Morgan, Lewis & Bockius, LLP, 1701 Market Street, Philadelphia, PA 19103-2921,
Attention: Eric Stern; provided, however, that any notice to an Underwriter
pursuant to Section 7 will be mailed, delivered or telegraphed and confirmed to
such Underwriter.

     11.  SUCCESSORS. This Agreement will inure to the benefit of and be binding
upon the parties hereto and their respective successors and the officers and
directors and controlling persons referred to in Section 7, and no other person
will have any right or obligation hereunder.

     12.  REPRESENTATION OF UNDERWRITERS. The Representatives will act for the
several Underwriters in connection with this financing, and any action under
this Agreement taken by the Representatives jointly or by CSFBC will be binding
upon all the Underwriters.

     13.  COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be deemed to be an original, but all such
counterparts shall together constitute one and the same Agreement.

     14.  APPLICABLE LAW. THIS AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES
OF CONFLICTS OF LAWS.

     The Company hereby submits to the non-exclusive jurisdiction of the Federal
and state courts in the Borough of Manhattan in The City of New York in any suit
or proceeding arising out of or relating to this Agreement or the transactions
contemplated hereby.


<Page>


     If the foregoing is in accordance with the Representatives' understanding
of our agreement, kindly sign and return to the Company one of the counterparts
hereof, whereupon it will become a binding agreement between the Company and the
several Underwriters in accordance with its terms.

                                    Very truly yours,

                                          CORPORATE OFFICE PROPERTIES TRUST


                                                By:
                                                   -----------------------------
                                                   Name:
                                                   Title:


                                          CORPORATE OFFICE PROPERTIES, L.P.

                                          By: CORPORATE OFFICE PROPERTIES TRUST,
                                              its sole general partner



                                                By:
                                                   -----------------------------
                                                   Name:
                                                   Title:


The foregoing Underwriting Agreement is hereby
 confirmed and accepted as of the date first
 above written.

     CREDIT SUISSE FIRST BOSTON CORPORATION
     A.G. EDWARDS & SONS, INC.

          Acting on behalf of themselves and as the
           Representatives of the several Underwriters

     By:  CREDIT SUISSE FIRST BOSTON CORPORATION


      By:
         ---------------------------------------
         Name:
         Title:


<Page>

                                   SCHEDULE I

<Table>
<Caption>

                                                                                    Number of
                               Underwriter                                       Firm Securities
                               -----------                                       ---------------
                                                                              
Credit Suisse First Boston Corporation...........................................   231,500
A.G. Edwards & Sons, Inc.........................................................   231,500
Legg Mason Wood Walker, Incorporated.............................................   111,000
Prudential Securities Incorporated...............................................   111,000
BB&T Capital Markets.............................................................   111,000
Ferris, Baker Watts, Incorporated................................................   111,000
Janney Montgomery Scott LLC......................................................   111,000
McDonald Investments Inc.........................................................   111,000
Tucker Anthony Incorporated......................................................   111,000
                                                                                 ----------
                           Total................................................. 1,240,000
                                                                                 ==========
</Table>


<Page>


                                   SCHEDULE II

                                  SUBSIDIARIES

<Table>
<Caption>

                                                                  Jurisdiction of
                          Name                                Incorporation/Formation          Foreign Qualification
                          ----                                -----------------------          ---------------------
                                                                                         
             LIMITED & GENERAL PARTNERSHIPS
             ------------------------------
Blue Bell Investment Company, L.P.                                   Delaware                           PA
Corporate Office Properties, L.P.                                    Delaware                       MD, NJ, PA
Corporate Gateway General Partnership                                   PA
Comcourt Investors, L.P.                                             Delaware                           PA
COPT Gateway, L.P.                                                      PA
Gateway Central Limited Partnership                                     PA
South Brunswick Investors, L.P.                                      Delaware                           NJ
6385 Flank Drive, L.P.                                                  PA

CORPORATIONS
- ------------
Corporate Office Management, Inc.                                    Maryland                     NJ, DE, VA, PA
Corporate Office Properties Holdings, Inc.                           Delaware                         PA, NJ
COPT Acquisitions, Inc.                                              Delaware                       PA, NJ, MD

LIMITED LIABILITY COMPANIES
- ---------------------------
Airport Square II, LLC                                               Maryland
Delaware Airport III, LLC                                            Delaware                           MD
Airport Square IV, LLC                                               Maryland
Airport Square V, LLC                                                Maryland
Airport Holdings Square VI and VII, LLC                              Delaware                           MD
Delaware Airport VIII, LLC                                           Delaware                           MD
Delaware Airport IX, LLC                                             Delaware                           MD
Airport Square X, LLC                                                Maryland
Airport Square XI, LLC                                               Maryland
Airport Square XIII, LLC                                             Maryland
Airport Square XIV, LLC                                              Maryland
Airport Square XV, LLC                                               Maryland
Airport Square XIX, LLC                                              Maryland
Airport Square XX, LLC                                               Maryland
Airport Square XXI, LLC                                              Maryland
Airport Square XXII, LLC                                             Maryland
Airport Square Partners, LLC                                         Maryland
Airport Square, LLC                                                  Maryland
Airport Square Holdings, I, LLC                                      Delaware                           MD
Atrium Building, LLC                                                 Maryland
Brown's Wharf, LLC                                                   Maryland
Commons Office Research, LLC                                         Maryland
Concourse 1304, LLC                                                  Maryland
COPT Columbia, LLC                                                   Maryland
COPT Concourse, LLC                                                  Delaware
</Table>


<Page>


                              SCHEDULE II (CONT'D.)
                                  SUBSIDIARIES

<Table>
<Caption>

                                                                  Jurisdiction of
                          Name                                Incorporation/Formation          Foreign Qualification
                          ----                                -----------------------          ---------------------
                                                                                         
LIMITED LIABILITY COMPANIES (CONT.)
- -----------------------------------
COPT Gate 6700-6708-6724, LLC                                         Maryland
COR, LLC                                                              Maryland
Corporate Development Services, LLC                                   Maryland
Corporate Gatespring, LLC                                             Maryland
Corporate Gatespring II, LLC                                          Maryland
Corporate Management Services, LLC                                    Maryland
Corporate Realty Management, LLC                                      Maryland                   DC, VA, DE, PA, NJ
Corporate Realty Advisors, LLC                                        Maryland
Cornucopia Holdings, LLC                                              Maryland
Cornucopia Holdings II, LLC                                           Maryland
CRM/Edgewood Property Services, LLC                                   Maryland
Cuaba Associates, LLC                                                New Jersey
Gateway 44, LLC                                                       Maryland
Gateway 70, LLC                                                       Maryland
Honeyland 108, LLC                                                    Maryland
Lakeview at the Greens, LLC                                           Maryland
Martin G. Knott & Associates, LLC                                     Maryland
NBP One, LLC                                                          Maryland
NBP 131-133-141, LLC                                                  Maryland
NBP 132, LLC                                                          Maryland
NBP 134, LLC                                                          Maryland
NBP 135, LLC                                                          Maryland
NBP 201, LLC                                                          Maryland
NBP 221, LLC                                                          Maryland
NBP Retail, LLC                                                       Maryland
9690 Deereco Road, LLC                                                Maryland
Princeton Executive, LLC                                             New Jersey
7200 Riverwood, LLC                                                   Maryland
7318 Parkway Drive Enterprises, LLC                                   Maryland
7321 Parkway Drive Enterprises, LLC                                   Maryland
7240 Parkway Drive Enterprises, LLC                                   Maryland
6711 Gateway, LLC                                                     Maryland
6731 Gateway, LLC                                                     Maryland
68 Culver, LLC                                                       New Jersey
St. Barnabas, LLC                                                     Maryland
Tech Park I, LLC                                                      Maryland
Tech Park II, LLC                                                     Maryland
Tech Park IV, LLC                                                     Maryland
Three Centre Park, LLC                                                Maryland
</Table>


<Page>


                                  SCHEDULE III

                               MATERIAL DOCUMENTS


     Amended and Restated Registration Rights Agreement, dated March 16, 1998,
for the benefit of certain shareholders of the Company (filed with the Company's
Quarterly Report on Form 10-Q on August 12, 1998 and incorporated herein by
reference).

     Second Amended and Restated Limited Partnership Agreement of the Operating
Partnership, dated December 7, 1999 (filed with the Company's Annual Report on
Form 10-K on March 16, 2000 and incorporated herein by reference).

     First Amendment to Second Amended and Restated Limited Partnership
Agreement of the Operating Partnership, dated December 21, 1999 (filed with the
Company's Annual Report on Form 10-K on March 16, 2000 and incorporated herein
by reference).

     Second Amendment to Second Amended and Restated Limited Partnership
Agreement of the Operating Partnership, dated December 21, 1999 (filed with the
Company's Post Effective Amendment No. 2 to Form S-3, dated November 1, 2000
(Registration Statement No. 333-71807), and incorporated herein by reference).

     Third Amendment to Second Amended and Restated Limited Partnership
Agreement of the Operating Partnership, dated September 29, 2000 (filed with the
Company's Post Effective Amendment No. 2 to Form S-3, dated November 1, 2000
(Registration Statement No. 333-71807), and incorporated herein by reference).

     Sixth Amendment to Second Amended and Restated Limited Partnership
Agreement of the Operating Partnership, dated April 3, 2001 (filed with the
Company's Current Report on Form 8-K, dated March 30, 2001, and incorporated
herein by reference).

     Registration Rights Agreement, dated September 28, 1998, for the benefit of
certain shareholders of the Company.

     Senior Secured Credit Agreement, dated October 13, 1997, (filed with the
Company's Current Report on Form 8-K on October 29, 1997, and incorporated
herein by reference).

     Amended and Restated Senior Secured Credit Agreement, dated August 31,
1998, between the Company, the Operating Partnership, Any Mortgaged Property
Subsidiary and Bankers Trust Company as Agent.

     Project Consulting and Management Agreement, dated September 28, 1998,
between Constellation Properties, Inc. and COMI (filed with the Company's
Current Report on Form 8-K on October 13, 1998 and incorporated herein by
reference).

     Agreement for Services, dated September 28, 1998, between the Company and
Corporate Office Management, Inc.

     Promissory Note dated October 22, 1998, in the amount of $ 85,000,000 made
by the Operating Partnership in favor of Teachers Insurance and Annuity
Association of America.


<Page>


                                   SCHEDULE IV

                           SUBSIDIARIES - MLB OPINION


Corporate Office Properties, L.P.
Corporate Office Management, Inc.
Corporate Realty Management, LLC
Corporate Development Services, LLC
Blue Bell Investment Company, L.P.
South Brunswick Investors, L.P.


<Page>


                                   SCHEDULE V

                          SUBSIDIARIES - GURLEY OPINION


NBP One, LLC
Airport Square II, LLC
Airport Square XX, LLC
NBP 131-133-141, LLC
NBP 135, LLC
7200 Riverwood, LLC
Corporate Gatespring, LLC
St. Barnabas, LLC