Sec Form 3 Filing - HEATH JAMES R @ IsoPlexis Corp - 2021-10-07

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person HEATH JAMES R 2. Issuer Name and Ticker or Trading Symbol IsoPlexis Corp [ ISO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O ISOPLEXIS CORPORATION, 35 NE INDUSTRIAL RD 3. Date of Earliest Transaction (MM/DD/YY) 10/07/2021 (Street) BRANFORD, CT06405 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (right to buy) $ 0.1275 ( 1 ) 03/21/2025 Common Stock 81,888 ( 1 ) D Stock Option (right to buy) $ 0.2788 ( 2 ) 11/25/2025 Common Stock 32,000 ( 2 ) D Stock Option (right to buy) $ 0.44 ( 3 ) 08/17/2026 Common Stock 40,000 ( 3 ) D Stock Option (right to buy) $ 0.7263 ( 4 ) 09/30/2027 Common Stock 48,000 ( 4 ) D Stock Option (right to buy) $ 0.9625 ( 5 ) 12/13/2028 Common Stock 32,000 ( 5 ) D Stock Option (right to buy) $ 1.83 ( 6 ) 12/14/2030 Common Stock 8,000 ( 6 ) D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other HEATH JAMES R C/O ISOPLEXIS CORPORATION 35 NE INDUSTRIAL RD BRANFORD, CT06405 X Signatures /s/ Shane Sevier, attorney-in-fact for James R. Heath 10/07/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents 81,888 time-vesting options. Time-vesting options were subject to a four-year time-based vesting schedule, with 25% vested on March 22, 2016 and the remainder vested in 36 equal installments every month thereafter. ( 2 )Represents 32,000 time-vesting options. Time-vesting options were subject to a four-year time-based vesting schedule, with 25% vested on November 26, 2016 and the remainder vested in 36 equal installments every month thereafter. ( 3 )Represents 40,000 time-vesting options. Time-vesting options were subject to a four-year time-based vesting schedule, with 25% vested on August 18, 2017 and the remainder vested in 36 equal installments every month thereafter. ( 4 )Represents 48,000 time-vesting options. Time-vesting options are subject to a four-year time-based vesting schedule, with 25% vested on October 1, 2018 and the remainder vesting in 36 equal installments every month thereafter. ( 5 )Represents 32,000 time-vesting options. Time-vesting options are subject to a four-year time-based vesting schedule, with 25% vested on December 5, 2019 and the remainder vesting in 36 equal installments every month thereafter. ( 6 )Represents 8,000 time-vesting options. Time-vesting options are subject to a four-year time-based vesting schedule, with 25% vesting on December 15, 2021 and the remainder vesting in 36 equal installments every month thereafter.

Remarks: Exhibit 24 - Power of Attorney

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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