Studies on ruthenium-terpyridyl-bypyridyl complexes as photosensitizers for dye sensitized solar cells are very few mostly due to their less appealing photophysics and lability of the ancillary ligands. In this book the author has done a comparative study of a series of such complexes which are appended with moieties of contrasting electronic properties on the terpyridine ligand. The observed absorbance, electrochemical and photovoltaic trends along with their theoretical studies have been discussed to find out a definite structure-activity relationship for this type of photosensitizers.