Help three founders mediate a dispute
byoung2: C doesn't deserve compensation for the introduction alone.  Maybe he could get something if he had some part of OldCo's intellectual property (e.g. he wrote some code, etc.).  The "startup world" is still just business.  Consider the same situation in another industry:Imagine A, B, and C were members of a rock band and C goes solo.  C later meets with Record Label 1 who is interested in a country trio.  A, B, and C reunite as a country trio and pitch their demo to the record label who declines.  A and B then return to the rock band, and C goes solo again.  Record Label 1, now well-acquainted with A and B, introduces them to Record Label 2, who, along with Record Label 1, signs A and B's rock band.  I doubt any band would ever be expected to give up a portion of future royalties to a former member (unless he had rights to songs, recordings, etc.).