The main results of the study of the polymer composites of polymethine dyes photosensitive in a wide spectral range including the near IR region are presented. The high photosensitivity was observed in the composites with high concentration of polymethine dyes. The basic reason for widening the spectral region of photosensitivity for these composites is the formation of aggregates in them, for which the energy and efficiency of photogeneration of charge carriers are higher than those for quasiisolated molecules of polymethine dyes. The studied polymer composites of polymethine dyes can be used as near IR radiation sensors (800-1400 nm) and plastic photovoltaic solar cells.