A trinuclear [{Ru II (bpy) 2 (bpy-terpy)} 2 Fe II ] 6+ complex ( I ) in which a Fe II -bis-terpyridine-like centre is covalently linked to two Ru II -tris-bipyridine-like moieties by a bridging bipyridine-terpyridine ligand has been synthesised and characterised. Its electrochemical, photophysical and photochemical properties have been investigated in CH 3 CN and compared with those of mononuclear model complexes. The cyclic voltammetry of ( I ) exhibits, in the positive region, two successive reversible oxidation processes, corresponding to the Fe III /Fe II and Ru III /Ru II redox couples. These systems are clearly separated (Δ E 1/2 = 160 mV), demonstrating the lack of an electronic connection between the two subunits. The two oxidized forms of the complex, [{Ru II (bpy) 2 (bpy-terpy)} 2 Fe III ] 7+ and [{Ru III (bpy) 2 (terpy-bpy)} 2 Fe III ] 9+ , obtained after two successive exhaustive electrolyses, are stable. ( I ) is poorly luminescent, indicating that the covalent linkage of the Ru II -tris-bipyridine to the Fe II -bis-terpyridine subunit leads to a strong quenching of the Ru II * excited state by energy transfer to the Fe II centre. Luminescence lifetime experiments show that the process occurs within 6 ns. The nature of the energy transfer process is discussed and an intramolecular energy exchange is proposed as a preferable deactivation pathway. Nevertheless this energy transfer can be efficiently quenched by an electron transfer process in the presence of a large excess of the 4-bromophenyl diazonium cation, playing the role of a sacrificial oxidant. Finally complete photoinduced oxidation of ( I ) has been performed by continuous photolysis experiments in the presence of a large excess of this sacrificial oxidant. The comparison with a mixture of the corresponding mononuclear model complexes has been made.