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                                                                    EXHIBIT 5(c)





                        [Mayer, Brown & Platt Letterhead]




                                 June 15, 2001


Comerica Incorporated
500 Woodward Avenue, MC 3391
Detroit, Michigan 48226

Comerica Capital Trust I
Comerica Capital Trust II
c/o Comerica Incorporated
500 Woodward Avenue, MC 3391
Detroit, Michigan 48226

         Re:  Registration Statement on Form S-3

Ladies and Gentlemen:

         We have acted as counsel to (i) Comerica Incorporated, a Delaware
corporation (the "Company"), and (ii) Comerica Capital Trust I and Comerica
Capital Trust II (each, a "Trust" and, together, the "Trusts"), each a statutory
business trust created under the Business Trust Act of the State of Delaware, in
connection with the preparation of a Registration Statement on Form S-3 (the
"Registration Statement"), to be filed by the Company and the Trusts with the
Securities and Exchange Commission under the Securities Act of 1933, as amended
(the "Act"). The Registration Statement relates to the issuance and sale
pursuant to Rule 415 under the Act of the following securities with an aggregate
public offering price of up to $350,000,000: (i) Preferred Securities (the
"Preferred Securities") of the Trusts; (ii) Junior Subordinated Debentures of
the Company (the "Debentures"); and (iii) the rights of holders of the Preferred
Securities under a guarantee (the "Preferred Securities Guarantee") by the
Company.

         The Preferred Securities are to be issued pursuant to an Amended and
Restated Declaration of Trust (the "Trust Agreement"), among the Company, as
sponsor and as the issuer of the Debentures to be held by the Property Trustee
(as defined below), Chase Manhattan Bank USA, National Association, as Delaware
Trustee, Chase Manhattan Trust Company, N.A., as property trustee (the "Property
Trustee"), and the regular trustees named therein. The Preferred Securities
Guarantee will be issued pursuant to a Guarantee Agreement (the "Guarantee


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Comerica Incorporated
Comerica Capital Trust I
Comerica Capital Trust II
June 15, 2001



Agreement") by the Company, as guarantor.

         This opinion is being delivered in accordance with the requirements of
Item 601 (b)(5) of Regulation S-K under the Act. Capitalized terms used but not
otherwise defined herein have the meanings ascribed to them in the Registration
Statement.

         In connection with this opinion, we have examined originals or copies,
certified or otherwise identified to our satisfaction, of: (i) the Registration
Statement; (ii) the Certificates of Trust of the Trusts filed with the Secretary
of State of the State of Delaware on June 13, 2001, 2001; (iii) the form of the
Trust Agreement (including the designations of the terms of the Preferred
Securities annexed thereto); (iv) the form of the Preferred Securities and
specimen certificates thereof; (v) the form of the Guarantee Agreement; (vi) the
form of the subordinated indenture (the "Indenture"), between the Company and
Chase Manhattan Trust Company, N.A., as indenture trustee, pursuant to which the
Debentures will be issued; (vii) a specimen Debenture; (viii) the Restated
Certificate of Incorporation of the Company, as presently in effect; (ix) the
By-Laws of the Company, as presently in effect; and (x) certain resolutions of
the Board of Directors of the Company relating to the issuance and sale of the
Debentures and the Preferred Securities and related matters. We have also
examined originals or copies, certified or otherwise identified to our
satisfaction, of such other documents, certificates and records as we have
deemed necessary or appropriate as a basis for the opinions set forth herein.

         In expressing the opinions set forth below, we have assumed the
genuineness of all signatures, the conformity to originals of all documents
reviewed by us as copies, the authenticity and completeness of all original
documents reviewed by us in original or copy form and the legal competence of
each individual executing any document. In making our examination of executed
documents or documents to be executed, we have assumed that the parties thereto,
other than the Company and the Trusts, had or will have the power to enter into
and perform all obligations thereunder and have also assumed the due
authorization by all requisite action, corporate or other, and execution and
delivery by such parties of such documents and that such documents constitute
valid and binding obligations of such parties.

         Based on and subject to the foregoing and to the other qualifications
and limitations set forth herein, we are of the opinion that when: (i) the
Registration Statement becomes effective; (ii) the Indenture, the Trust
Agreement and the Guarantee Agreement have been qualified under the Trust
Indenture Act of 1939, as amended, (iii) matters relating to the issuance and
sale of the Preferred Securities and the Debentures have been duly adopted by
the Board of Directors of the Company; (iv) the Trust Agreement, the Guarantee
Agreement and the Indenture have been duly executed and delivered by the parties
thereto; (v) the Preferred Securities have been duly executed and authenticated
in accordance with the terms of the Trust Agreement and duly delivered to the
purchasers thereof against payment of the agreed consideration therefor; and
(vi)


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Comerica Incorporated
Comerica Capital Trust I
Comerica Capital Trust II
June 15, 2001



the Debentures have been duly executed and authenticated in accordance with
the terms of the Indenture and delivered to and paid for by the Trusts as
contemplated by the Trust Agreement:

                  (i) The Company is validly existing as a corporation in good
         standing under the laws of the State of Delaware.

                  (ii) The Guarantee Agreement will be a valid and binding
         obligation of the Company, enforceable against the Company in
         accordance with its terms, except to the extent that enforcement
         thereof may be limited by bankruptcy, insolvency, reorganization,
         moratorium or other similar laws affecting creditors' rights generally
         or by general principles of equity (regardless of whether enforcement
         is considered at law or in equity); and

                  (iii) The issuance and sale of the Debentures will have been
         duly authorized and the Debentures will be valid and binding
         obligations of the Company, entitled to the benefits of the Indenture
         and enforceable against the Company in accordance with their terms,
         except to the extent that enforcement thereof may be limited by
         bankruptcy, insolvency, reorganization, moratorium or other similar
         laws affecting creditors' rights generally or by general principles of
         equity (regardless of whether enforcement is considered at law or in
         equity).

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the use of our name under the caption "Legal
Matters" in the prospectus that forms a part of the Registration Statement. In
giving this consent, we do not thereby admit that we are within the category of
persons whose consent is required by Section 7 of the Securities Act of 1933.

         We are admitted to practice law in the States of Illinois and New York
and our opinions expressed herein are limited solely to the Federal laws of the
United States of America, the laws of the States of Illinois and New York and
the General Corporation Law of the State of Delaware.

                                          Very truly yours,



                                          /s/  Mayer, Brown & Platt
                                          MAYER, BROWN & PLATT