<PAGE>
                                                                   Exhibit 10.78

                               PURCHASE AGREEMENT


     This Purchase Agreement (this "Agreement"), dated as of May 9, 2002, is by
and among Cohen & Steers Capital Management, Inc. ("Cohen & Steers"), the client
accounts of Cohen & Steers, as set forth on Schedule A (each a "PURCHASER" and
collectively the "PURCHASERS"), and Kramont Realty Trust (the "SELLER").

     WHEREAS, the PURCHASERS, desire to purchase from SELLER, and SELLER desires
to issue and sell to PURCHASERS, in the aggregate 2,300,000 common shares of
beneficial interest of SELLER, par value $0.01 per share (the "Shares"), with
the number of Shares acquired by each PURCHASER set forth on Schedule A.

     NOW, THEREFORE, in consideration of the mutual promises herein contained,
the parties hereto agree as follows:

     1. Purchase and Sale. Subject to the terms and conditions hereof, the
PURCHASERS hereby agree to purchase from SELLER, and SELLER agrees to issue and
sell to PURCHASERS, the Shares at a price per share of $13.65 for an aggregate
purchase amount of $31,395,000 (the "Purchase Price").

     2. Representations and Warranties of PURCHASER. Each PURCHASER represents
and warrants that:

                 (a) Due Authorization. The PURCHASER is duly authorized to
         purchase the Shares. This Agreement has been duly authorized, executed
         and delivered by the PURCHASER and constitutes a legal, valid and
         binding agreement of the PURCHASER, enforceable against the PURCHASER
         in accordance with its terms except as may be limited by (i) the effect
         of bankruptcy, insolvency, reorganization, moratorium or other similar
         laws relating to or affecting the rights or remedies of creditors or
         (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.

                 (b) Prospectus and Prospectus Supplement. The PURCHASER has
         received a copy of SELLER's Prospectus dated April 3, 2002, and
         Prospectus Supplement dated May 9, 2002 (collectively, the
         "Prospectus").

     3. Representations and Warranties of SELLER. SELLER represents and warrants
that:

                 (a) Due Authorization. This Agreement has been duly authorized,
<PAGE>
          executed and delivered by SELLER and constitutes a legal, valid and
          binding agreement of SELLER, enforceable against SELLER in accordance
          with its terms except as may be limited by (i) the effect of
          bankruptcy, insolvency, reorganization, moratorium or other similar
          laws relating to or affecting the rights or remedies of creditors or
          (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.

               (b) Organization and Authority. SELLER has been duly organized
          and is validly existing in good standing under the laws of Maryland,
          with full power and authority to own or lease and occupy its
          properties and conduct its business as described in the Prospectus.

               (c) Issuance of the Shares. The Shares have been duly and validly
          authorized and, when issued and delivered pursuant to this Agreement,
          will be fully paid and nonassessable and will be listed, subject to
          notice of issuance, on the New York Stock Exchange effective as of the
          Closing (as defined in Paragraph 5 of this Agreement).

               (d) Absence of Conflicts. The execution, delivery and performance
          of this Agreement and the consummation of transactions contemplated
          herein do not and will not result in the creation or imposition of any
          lien, charge or encumbrance upon any property or assets of the SELLER.

     4. Representation and Warranty of Cohen & Steers. Cohen & Steers hereby
represents and warrants that:

               (a) It is an investment adviser duly registered with the
          Securities and Exchange Commission under the Investment Advisers Act
          of 1940.

               (b) It has been duly authorized to act as investment adviser on
          behalf of each PURCHASER.

               (c) It has the power and authority to enter into and execute this
          Agreement on behalf of each PURCHASER.

               (d) This Agreement has been duly executed and delivered by Cohen
          & Steers and constitutes a legal, valid and binding agreement of Cohen
          & Steers, enforceable against Cohen & Steers in accordance with its
          terms except as may be limited by (i) the effect of bankruptcy,
          insolvency, reorganization, moratorium or other similar laws relating
          to or affecting the rights or remedies of creditors or (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.


                                       2
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     5. Conditions to Obligations of the Parties. As a condition to Closing,
each of the representations and warranties of the parties hereto shall be true
and correct in all respects.

     6. Closing. The transactions contemplated hereby shall be consummated on
May 16, 2002 (such time and date of payment and delivery being herein called the
"Closing"). At the Closing, settlement shall occur through Jeffries & Company,
Inc., or an affiliate thereof, on a delivery versus payment basis through the
DTC ID System.

     7. Governing Law. This Agreement shall be construed in accordance with and
governed by the substantive laws of the State of New York.

     8. Entire Agreement. This Agreement constitutes the entire agreement
between the parties hereto with respect to the subject matter hereof and may be
amended only in a writing that is executed by each of the parties hereto.

     9. Counterparts. This Agreement may be executed in separate counterparts,
each of which shall be deemed an original, and all of which together shall be
deemed to constitute one and the same instrument.


                                       3
<PAGE>
     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed and delivered as of the date first above written.

                    KRAMONT REALTY TRUST



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


               COHEN & STEERS CAPITAL MANAGEMENT, INC., on behalf of itself and
          each PURCHASER set forth on Schedule A

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


                                       4
<PAGE>
                                   SCHEDULE A

<TABLE>
<CAPTION>
Name of Client                                      Number of Shares
--------------                                      ----------------
<S>                                                 <C>
Fairfax County Uniformed Retirement System                4,000
North Shore-Long Island Jewish
Health System Cash Balance Plan                           2,900
New York State Teachers' Retirement System               61,000
Cohen & Steers Total Return Realty Fund, Inc.            36,600
Cohen & Steers Advantage Income Realty Fund, Inc.       800,000
Cohen & Steers Quality Income Realty Fund, Inc.       1,291,300
University of Mass. Foundation Inc.                       2,000
United Mine Workers of America 1974 Pension Trust        24,900
Babson College                                            3,700
Admiral Reinsurance Company                              73,600
</TABLE>