Various redox chromophores were highly organized in Langmuir-Blodgett (LB) films to show specific photoresponses such as colour changes due to photoinduced electron transfer (photoinduced electrochromism), anisotropic orientation of photogenerated radicals, molecular control of photocurrents, and dispersive deactivation of excited triplet states. Colour changes due to the photoinduced electron transfer reaction and molecular control of photogenerated radicals were achieved in LB films. Photoinduced electrochromism of a single monolayer LB film in amphiphilic 4,4′-bipyridinium was successfully detected by the optical waveguide (OWG) method. Transient absorption upon excitation of amphiphilic porphyrin in LB films with a nanosecond laser of 532 nm was also sensitively detected by this method. The excited triplet porphyrin decayed with a dispersive process in LB films indicating inhomogeneous distribution of chromophores. Anisotropic photoconduction and its molecular control were achieved in LB films.