A heterodinuclear complex based on a RuII鈥揟PA [TPA = tris(2-pyridylmethyl)amine] complex having a peripheral CuII(bpy)2 (bpy = 2,2鈥?bipyridine) group bonded through an amide linkage displayed reversible intramolecular electron transfer between the Ru and Cu complex units that can be controlled by protonation and deprotonation of the bridging amide moiety.