No emission of photoexcited Ru(bpy)(3) was found in Fe and Mn porphyrin-Ru(bpy)(3) conjugates. In the case of free-base and Zn porphyrin-Ru(bpy)(3) conjugates, quenching of Ru(bpy)(3) emission and the appearance of considerable free-base and Zn porphyrin emissions were found. The excitation spectra of these emissions revealed however that these emissions originate from the corresponding excitation of free-base and Zn porphyrin moieties. These observations suggest efficient intramolecular electron transfer from the photoexcited Ru(bpy)(3) moiety to the free-base, Zn, Fe and Mn porphyrins. (C) 2000 Elsevier Science Ltd. All rights reserved.