The main results of studies of the effect of a polymer molecular structure on the photosensitivity of composites films based on infra-red polymethine dye photosensitive in a wide spectral range including the near IR region are presented. The highest photosensitivity is observed among the studied composites in that with a polyphenylenevinylene polymer matrix. The basic reason for high integral photosensitivity of these composites is the formation of aggregates, for which the energy and efficiency of the photogeneration of charge carriers are comparable or higher than those for quasiisolated molecules of polymethine dyes. The studied polymer composites of polymethine dyes can be used as near IR radiation sensors (800-1400nm) and IR photoconverters including solar cells.