Exciplex formation between N,N-dimethylaniline and a series of distyrylbenzene derivatives with varying structures was studied by cyclic voltammetry and fluorescence spectroscopy. The frequency of exciplex emission obeys the Weller equation. Increasing the electron affinity of the acceptor red-shifts emission, with a concomitant decrease in fluorescence efficiency. Increasing the conjugation length of the acceptor decreases its excited state singlet energy more quickly than its electron affinity. As a result, exciplex formation is discouraged with increasing conjugation length.