The mixed-metal supramolecular complexes [(tpy)Ru(tppz)PtCl](PF6)(3) and [ClPt(tppz)Ru(tppz)PtCl](PF6)(4) (tpy = 2,2':6',2"-terpyridine and tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) were synthesized and characterized. These complexes contain ruthenium bridged by tppz to platinum centers to form stereochemically defined linear assemblies. X-ray crystallographic determinations of the two complexes confirm the identity of the metal complexes and reveal intermolecular interactions of the Pt sites in the solid state for [(tpy)Ru(tppz)PtCl](PF6)(3) with Pt center dot center dot center dot Pt distance of 3.3218(5) angstrom. The H-1 NMR spectra show the expected splitting patterns characteristic of stereochemically defined mixed-metal systems and are assigned with the use of H-1-H-1 COSY and NOESY. Electronic absorption spectroscopy displays intense ligand-based pi ->pi* transitions in the UV and MLCT transitions in the visible. Electrochemically [(tpy)Ru(tppz)PtCl](PF6)(3) and [CiPt(tppz)Ru(tppz)PtCl](PF6)(4) display reversible Ru-II/III couples at 1.63 and 1.83 V versus Ag/AgCl, respectively. The complexes display very low potential tppz(0/-) and tppz(-/2-) couples, relative to their monometallic synthons, [(tpy)Ru(tppz)](PF6)(2) and [Ru(tPPZ)(2)](PF6)(2), consistent with the bridging coordination of the tppz ligand. The Ru(d pi) -> tppz(pi*) MLCT. transitions are also red-shifted relative to the monometallic synthons occurring in the visible centered at 530 and 538 nm in CH3CN for [(tpy)Ru(tppz)PtCl](PF6)(3) and [CiPt(tppz)Ru(tppz)PtCl](PF6)(4), respectively. The complex [(tpy)Ru(tppz)PtCl](PF6)(3) displays a barely detectable emission from the Ru(d pi) -> tppZ(pi*) (MLCT)-M-3 in CH3CN solution at RT. In contrast, [CIPt(tppz)Ru(tppz)PtCl](PF6)(4) displays an intense emission from the Ru(d pi) -> tppz(pi*) (MLCT)-M-3 state at RT with lambda(em)(max) = 754 nm and T = 80 ns.