The investigation of photochemical and photophysical properties of coordination compounds as well as experiments on solar cells carried out in our Laboratory of Inorganic Photochemistry and Energy Conversion are outlined here. They are discussed in parallel with the current state of knowledge in each topical area. Particular emphasis is given to the photochemical behavior of the [Fe(CN) 5 L] 3 - complexes including the solvent dependence for the photosubstitution of both L and CN - . The quantum yields for the photodissociation of a cyanide are also analyzed in terms of such effects as metric, topological, chelating and neighboring group effects on the photoinduced ring closure efficiency. The photophysics and photochemistry of some rhenium complexes are discussed, as well as some supramolecular photochemistry, in particular, ion-pair photochemistry of cobalt complexes and a covalently-linked Re-Ru system. Finally, the investigations on solar energy conversion and development of thin-layer solar cells based on sensitization of nanocrystalline TiO 2 semiconductor films by some ruthenium polypyridyl complexes are presented.