Photoenergy migration and hole transfer in a bilayer membrane composed of amphiphilic compounds carrying an N-ethylcarbazolyl group (5Cz18) were investigated. Photoenergy migration was evaluated by fluorescence quenching of the N-ethylcarbazolyl (ECz) group by methyl terephthaloyldioctadecylamide mixed in the bilayer membrane. The quenching data were well simulated by taking the number of energy migrations among ECz groups to be 360 below the phase-transition temperature (T-c) and 113 above the T-c. Two-photon excitation of the ECz group in the bilayer membrane produced a radical cation (hole). The lifetime of the cation in the bilayer membrane of 5Cz18 was 40 mu s above the T-c. It became longer below the T-c and upon dilution of the chromophores in the membrane, indicating that the rate of hole transfer is comparable to the lateral diffusion of the amphiphile in the membrane.