<PAGE>
                                                                   EXHIBIT 10.25


[MEMORY PHARMACEUTICALS CORP. LOGO]
MEMORY PHARMACEUTICALS CORP.                          Tony Scullion
100 Philips Parkway                                   Chief Executive Officer
Montvale, New Jersey 07645
Phone: (201) 802-7102
Fax: (201) 802-7190
www.memorypharma.com


December 16, 2003


Mr. Dennis Keane
50 Constant Avenue
Yonkers, NY 10701

Dear Dennis:

      We are pleased to inform you that both the Board of Directors and
management team of Memory Pharmaceuticals Corp. (the "Company") are impressed
with your experience and accomplishments, and would like to extend an offer to
you to join our Company as Chief Financial Officer. We look forward to you
joining our team, and are confident that you will contribute significantly to
the value of our organization. We are therefore pleased to provide you with the
terms of your anticipated employment by the Company.

      1. Position. In your position of Chief Financial Officer you will
initially report to the Company's Chief Executive Officer, based out of the
Company's offices currently located in Montvale, New Jersey. As Chief Financial
Officer, you will be part of the senior management team (comprising the senior
executives of the Company), and your responsibilities shall include, but not be
limited to, managing and directing the financial affairs of the Company. In
addition to performing duties and responsibilities associated with the position
of Chief Financial Officer, from time to time the Company may assign you other
duties and responsibilities and/or may assign you to a different location within
fifty (50) miles of the Company's principal office in Montvale, New Jersey.

      As a full-time employee of the Company, you will be expected to devote
your full business time and energies to the business and affairs of the Company.
Your performance will be reviewed formally after six months of employment and
annually thereafter at the end of each calendar year.

      2. Starting Date/Nature of Relationship. It is expected that your
employment will start on January 6, 2004 (the "Start Date"). No provision of
this letter shall be construed to create an express or implied employment
contract for a specific period of time. Either you or the Company may terminate
the employment relationship at any time and for any reason.

      3. Compensation.

         (a)  Your initial salary will be at the bi-weekly rate of $8,269.23
      (annualized at $215,000 per year).

         (b)  You will receive non-qualified stock options to purchase, at fair
      market value to be determined by the Company's Board of Directors
      (currently $0.90 per share), 300,000 Shares of Common Stock of Memory
      Pharmaceuticals Corp., which shall vest in quarterly increments over a
      period of four (4) years as described in the Stock Option Agreement, which
      you and the Company will enter into on or before the Start Date.
<PAGE>
         (c)  You will be eligible to receive annual bonus payments dependent on
      the performance of the Company and your individual performance, subject to
      the discretion of the Board of Directors. Your target bonus will be equal
      to twenty-five percent (25%) of your base salary, assuming the achievement
      of such Company and individual performance objectives.

         (d)  Upon termination for any reason, the Company shall pay you within
      two weeks of such termination, your current base salary earned through the
      termination date, plus accrued vacation, if any, and other benefits or
      payments, if any, to which you are entitled. In the event you are
      terminated by the Company, without "Cause" (as hereinafter defined), then
      the Company shall continue to pay you your bi-weekly rate in effect at the
      time of termination and provide and pay the Company's portion of your
      medical insurance for a period of six months. Further, for the period
      commencing seven months following such termination and ending twelve
      months after such termination, the Company shall continue to pay you your
      bi-weekly rate in effect at the time of termination and provide and pay
      the Company's portion of your medical insurance, except that such
      severance payments made to you during this period shall be reduced by all
      1099 and W-2 income earned or received by you during such period,
      including income earned or received from consulting services or temporary
      employment. The Company shall reconcile such payments with you quarterly,
      and any additional payments owed to you by the Company, and any payments
      owed to the Company by you, shall be paid respectively within two weeks
      following such reconciliation period. In addition, upon termination of
      your employment without "Cause," you will be entitled to accelerated
      vesting of your stock options as if your employment was terminated one
      year after your actual termination date. The Company shall not be
      obligated to continue any such payments to you or accelerate vesting of
      your stock options under this paragraph 3(e) in the event you materially
      breach the terms under the Confidentiality Agreement attached hereto.
      Notwithstanding any termination of your employment for any reason (with or
      without Cause), you shall continue to be bound by the provisions of the
      Confidentiality Agreement.

         (e)  For the purposes of this Section 3, "Cause" shall include (i) your
      conviction of a felony, either in connection with the performance of your
      obligations to the Company or otherwise, which adversely affects your
      ability to perform such obligations or materially adversely affects the
      business activities, reputation, goodwill or image of the Company, (ii)
      your willful disloyalty, deliberate dishonesty, breach of fiduciary duty,
      (iii) your breach of the terms of this Agreement, or your failure or
      refusal to carry out any material tasks assigned to you by the Company in
      accordance with the terms hereof, which breach or failure continues for a
      period of more than thirty (30) days after your receipt of written notice
      thereof from the Company, (iv) the commission by you of any act of fraud,
      embezzlement or deliberate disregard of a rule or policy of the Company
      known to you or contained in a policy and procedure manual provided to you
      which results in material loss, damage or injury to the Company, or (v)
      the material breach by you of any of the provisions of the Confidentiality
      and Noncompetition Agreement substantially in the form of Attachment A to
      this letter.

      4. Benefits. You will be entitled as an employee of the Company to receive
such benefits as are generally provided its employees and executives and for
which you are eligible in accordance with Company policy as in effect from time
to time. The Company retains the right to change, add or cease any particular
benefit relating to its employees and executives generally. At this time, the
Company is offering a benefit program, consisting of medical, dental, life and
short/long term disability insurance, as well as a 401(k) retirement plan and
flexible spending plan. You will be eligible for eight paid holidays, four
floating holidays and four weeks paid vacation per year. You will accrue
additional vacation days in accordance with Company policy.


      5. Confidentiality. The Company considers the protection of its
confidential information and proprietary materials to be very important.
Therefore, as a condition of your employment, you and the Company will become
parties to a Confidentiality and Noncompetition Agreement substantially in the
form of Attachment A to this letter (the "Confidentiality Agreement").

                                       2


<PAGE>
      6. General.

         (a)  This letter, together with the Confidentiality Agreement and the
      Stock Option Agreement, will constitute our entire agreement as to your
      employment by the Company and will supersede any prior agreements or
      understandings, whether in writing or oral.

         (b)  This letter shall be subject to and contingent upon the
      satisfactory results of a medical physical. The Company will accept a
      summary of a medical examination by your family doctor within the past
      month.

         (c)  This letter shall be subject to and contingent upon the
      satisfactory review of references and personal background review.

         (d)  This letter and the Company's obligations hereunder shall be
      subject to review and approval by the Company's Board of Directors and
      the Compensation Committee thereof.

         (e)  This letter shall be governed by the law of the State of New
      Jersey.

      You may accept this offer of employment and the terms thereof by signing
the enclosed additional copy of this letter, the Confidentiality Agreement and
the Stock Option Agreement, which execution will evidence your agreement with
the terms set forth herein and therein, and returning all three documents to the
Company.

      This offer of employment will expire on December 18, 2003, unless accepted
by you prior to such date. We look forward to you joining our team, and we
believe that your skills will compliment those of our existing management team,
and that you will make a significant contribution to the Company's growth. We
look forward to your prompt response to this offer letter.

Sincerely,

MEMORY PHARMACEUTICALS CORP.


By:  /s/ Tony Scullion
    ----------------------
Name:  Tony Scullion
Title: Chief Executive Officer



ACCEPTED AND AGREED:

/s/ Dennis Keane
--------------------------
Dennis Keane

Date:   12/16/03
      --------------------


                                       3