EXHIBIT 1


January 25, 1995



Board of Directors
FirstRock Bancorp, Inc.
612 North Main Street
Rockford, Illinois  61103

Members of the Board:

You have  requested  our opinion as to the fairness of the merger  consideration
(the  "Merger   Consideration"),   from  a  financial  point  of  view,  to  the
shareholders  of  FirstRock  Bancorp,  Inc.  ("FirstRock")  with  respect to the
proposed merger of FirstRock with and into First Financial  Corporation  ("First
Financial").  FirstRock has entered into an Agreement and Plan of Reorganization
and a related Agreement and Plan of Merger (collectively the "Agreements"), both
dated October 26, 1994,  between First Financial and FirstRock.  As is set forth
in the Agreements,  each outstanding  share of common stock of FirstRock will be
converted  into and be  exchangeable  for the number of shares of Common  Stock,
$1.00 par value per share, of First Financial equal to a fraction, the numerator
of which shall be equal to $27.10 and the denominator of which shall be equal to
the  average  closing  price  per share of Common  Stock of First  Financial  as
reported on the Nasdaq Stock  Market for the fifteen  trading days ending on the
fourth trading day prior to the Effective Date of the Merger.

During the course of our engagement, we have, among other things:

       1)    reviewed  the  Agreements,  the  audited  financial  statements  of
             FirstRock  and First  Financial  for the most recent  three  fiscal
             years, and unaudited  financial  statements  through  September 30,
             1994 as reported on Form 10-Q, Office of Thrift Supervision ("OTS")
             Thrift Financial Reports of FirstRock,  as well as other internally
             generated FirstRock reports relating to asset/liability management,
             asset quality and so forth;

       2)    reviewed and analyzed other material bearing upon the financial and
             operating  condition of First  Financial and FirstRock and material
             prepared in connection  with the proposed  transaction;  

       3)    reviewed the operating  characteristics  of certain other financial
             institutions deemed relevant to the contemplated transaction;

       4)    reviewed   the  nature   and  terms  of  recent   sale  and  merger
             transactions  involving  banks,  thrifts,  bank and thrift  holding
             companies  and  other  financial   institutions  that  we  consider
             relevant;

January  25, 1995
Board of Directors
FirstRock Bancorp, Inc.
Page -2-


       5)    reviewed historical and current market data for First Financial and
             FirstRock common stock;  

       6)    reviewed  financial  and  other  information  provided to us by the
             managements' of First Financial and FirstRock;


       7)    conducted  meetings with members of the senior  management of First
             Financial  and  FirstRock  for the purpose of reviewing  the future
             prospects of First Financial and FirstRock;

       8)    reviewed  certain  information  including  forecasts  pertaining to
             prospective cost savings and revenue  enhancements  relative to the
             proposed transactions;

       9)    evaluated the proforma ownership of First Financial common stock by
             FirstRock  shareholders,  relative  to the  proforma  condition  of
             FirstRock's  assets,  liabilities,   equity  and  earnings  to  the
             proforma company.

The  Chicago  Corporation,  as  part  of its  investment  banking  business,  is
continually  engaged in the  valuation of banks and bank holding  companies  and
thrifts and thrift holding companies in connection with mergers and acquisitions
as well as initial and  secondary  offerings of securities as well as valuations
for other  purposes.  The Chicago  corporation is a member of all principal U.S.
Securities exchanges and in the conduct of our broker-dealer activities may from
time to time purchase  securities  from, and sell  securities to,  FirstRock and
First  Financial  and as a market  maker buy or sell the  equity  securities  of
FirstRock  for our own account and for the accounts of  customers.  In rendering
this  fairness  opinion  we have  acted  exclusively  on  behalf of the Board of
Directors of FirstRock and will receive a fee from FirstRock for our services.

In  rendering   this  opinion,   we  have  relied  upon,   without   independent
verification,   the  accuracy  and  completeness  of  the  financial  and  other
information and representations provided to us by First Financial and FirstRock.
We have relied upon the  management of FirstRock  and First  Financial as to the
reasonableness and achievability of the financial forecasts and projections (and
the assumptions and basis therefore)  provided to us, and have assumed that such
forecasts and projections are the best available estimates of management.

Based on the foregoing and our experience as investment  bankers,  we are of the
opinion that, as of the date hereof, the Merger  Consideration to be paid to the
shareholders  of  FirstRock  as  described  in the  Agreements,  is fair  from a
financial point of view.

Sincerely,



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/s/The Chicago Corporation

THE CHICAGO CORPORATION