Modification of wide band gap semiconductor surfaces by a new generation of supramolecular sensitizers, combining porphyrin and ruthenium-phenanthroline complexes leads to versatile molecular interfaces, allowing the exploitation of photoinduced charge transfer in dye sensitized photoelectrochemical cells. meso-Tetrapyridylporphyrin coordinated to two ruthenium complexes converts 21% of the incident photons into current after excitation at the Soret band. In this work we discuss the electron/energy transfer mechanisms involved in the TiO(2) sensitization by these supramolecular species, invoking some theoretical calculations.