The applications of photoinduced electron transfer, one in solar energy storage and the other in polymeric photorefractive materials are reported. In the former case, two new kinds of polymers containing norbornadiene and carbazole pendants were synthesized. The photoisomerization of norbornadiene pendants were achieved by irradiation with the light above the wavelength of 350 nm and a photoinduced electron transfer mechanism was proposed via fluorescence quenching, chemically induced dynamic nuclear polarization and thermodynamic discussion. In the latter case, a fast photorefractive response time of a polymer film composed of poly(N-vinylcarbazole), 2,4,7-trinitro-9-fluorenone and 4-(dicyanovinyl)-N,N-diethylaniline was observed by four-wave mixing diffraction measurement and the function of photoinduced electron transfer process in this photorefractive polymer film was also illustrated.