Photoinduced electron transfer has been studied for bridged donor/acceptor compounds incorporated in Langmuir-Blodgett (LB) films of phospholipid matrix, dioleoylphosphatidylcholine (DOPC). The compounds under investigation are zinc porphyrin (ZnP)-pyromellitimide (D1), ZnP-naphthalenetetracarboxamide (D2), and the derivatives of D1 and D2 with long alkyl chains in the ZnP ring periphery (D3 and D4, respectively). The kinetics of intra- or intermolecular electron transfer was investigated by probing fluorescence quenching of photoexcited ZnP* with the picosecond time-resolved fluorescence measurement. A fast intramolecular electron transfer occurs only in D4-LB film similarly to that in solution (tau(f) = 16 ps), but not in D1 and D3. In D2-LB film where D2 molecules are distributed as dimer and higher aggregates as well as monomer, an intermolecular electron transfer (tau(f) = 48 ps) occurs at dimer sites instead of the intramolecular reaction. To examine the spatial conformation of D2 dimer in LB monolayer films, the polarized absorption spectra were measured, suggesting a slightly slipped head-to-tail dimerization of two ZnP rings in which ZnP rings are tilted (15 degrees) to the substrate plane.