We have prepared the mononuclear complexes [Ru(bpy)2(AB)][PF6]2, [Ru(bpy)(AB)2][PF6]2, and [Ru(AB)3][PF6]2 (designated Ru − AB, Ru − AB 2 , and Ru − AB 3 , respectively) [where bpy is 2,2‘-bipyridine and AB is the asymmetric bis(bipyridyl) bridging ligand 2,2‘:3‘,2‘‘:6‘‘,2‘‘‘-quaterpyridine] in which there are one, two, or three (respectively) bpy-type fragments pendant from the {Ru(bpy)3}2+ core. In every case the less hindered site A of the ligand AB is coordinated to Ru(II) and the more hindered site B is pendant. Reaction with Re(CO)5Cl affords the heteronuclear complexes [Ru(bpy)2{ABRe(CO)3Cl}][PF6]2, [Ru(bpy){ABRe(CO)3Cl}2][PF6]2, and [Ru{ABRe(CO)3Cl}3][PF6]2 (designated Ru − ABRe, Ru − ABRe 2 , and Ru − ABRe 3 , respectively) in which each pendant site B is now coordinated to a {Re(CO)3Cl} fragment. Because of the conformational properties of the AB ligand, in the tetranuclear Ru − ABRe 3 complex the Ru-based chromophore occupies an internal position in a sort of molecular ball, the three Re-based groups being located outside. Electrochemical studies show that the pendant {Re(CO)3Cl} fragments exert an electron-withdrawing effect on the {Ru(bpy)3}2+ core such that the Ru(II)/Ru(III) redox couple moves to more positive potentials as the number of pendant {Re(CO)3Cl} fragments increases. We employed steady-state and time-resolved luminescence spectroscopy to investigate the Re → Ru intercomponent energy transfer taking place in the mixed-metal complexes and found that Re → Ru energy transfer takes place with 100% efficiency in all cases. For the tetranuclear complex, it is thus possible to convey a substantial portion of the electronic excitation energy from the molecular periphery to the center. It is also found that the peripheral Re-containing units exert a shielding effect against luminescence quenching processes at the Ru center by molecular oxygen dissolved in the solvent. During the syntheses, the unexpected byproduct [Ru(AB)(η3-AB)Cl][PF6] was also isolated in which one of the AB ligands is coordinated in a hitherto unseen terdentate mode; this was crystallographically characterized. Data for [Ru(AB)(η3-AB)Cl][PF6]·2MeCN:  C44H34ClF6N10PRu; triclinic, P1̄; a = 10.578(3) Å, b = 14.330(2) Å, c = 14.761(3) Å; α = 84.56(2)°, β = 70.408(12)°, γ = 86.03(2)°; V = 2096.8(8) Å3; Z = 2.