There has been considerable interest in the application of photochromism to photo-responsive systems which has led to the development of new tailored smart materials for photonics and biomedical fields. Within a polymeric matrix photochromic isomerizations can be stimulated by light to reversibly alter the physical and chemical properties of a material such as LC phase, shape, surface wettability, permeability, solubility, self-assembly, size and fluorescence. The underlying principles behind photoresponsive behavior, subsequent applications and relevant examples are discussed in this review.