Photochemistry is an important multidisciplinary scientific field at the forefront of research in chemistry, physics and biology, with numerous applications in modern technologies. Quintessence of the research in photochemistry is focused on the development of new functional chromophores with different applications. Within the proposed project we will work on three chromophores, BODIPY, carbazoles and biphenylamines, their synthesis and investigation of the photophysical properties and photochemical reactivity. Furthermore, we will try to find the applications of these chromophores in organic synthesis and biology. The BODIPY derivatives are excellent fluorescent dyes which will be investigated to develop new photo-cleavable protective groups (photocages) and intracellular fluorescent labels or drug delivery vehicles. The carbazole derivatives will be made with the aim to develop new line of cancer photo-therapeutics that base their action on generation of aza-quinone methides (aza-QM), and not singlet oxygen. Furthermore, we will work on the elucidation of reaction mechanism of aza-QM generation and its use in the synthesis of complex aza-heterocycles. The biphenylamine derivatives will be investigated as potential two-photon absorbing photocages that absorb visible light and can be used in biology. In addition to the fundamental character of the proposed investigation, we aim to go beyond the state of the art and seek applications, not only in organic synthesis, but also in biomedicine, such as development of new photo-activable drugs or new fluorescent reagents for the staining of organelles in microscopy. It is anticipated that the FunPhotoAppSynBio team will find a number of functional chromophores with biological activities (hit molecules), which will be further improved towards lead molecules. This will help in the development of new fluorescent tools in diagnostics and photo-treatments for cancer with minimal side-effects, with benefits to the whole society.