While modifying the molecular structure and applying a photochromic moiety, we can prepare a photosensitive systems that can become responsive towards the illumination of the light. Under light illumination with a specific wavelength we are changing the molecular structure of the target photosensitive compounds and therefore modify their mesomorphic properties. We study the photosensitivity of various types of molecular structures. We concentrate on azo-derivatives, which are sensitive to UV light and can transform from E-form to Z-form and vice versa. Besides, other sources of photochromic moieties are under search (spiropyrans, cinnamon derivatives etc.