Spectroscopic and electrochemical properties of a series of mixed-metal d(6),d(8) bimetallic complexes of the form [(bpy)(2)M(BL)PtCl2](2+) (bpy=2,2'-bipyridine; BL=dpq (2,3-bis(2-pyridyl)quinoxaline) or dpb (2,3-bis(2-pyridyl)benzoquinoxaline); M=Os-II or Ru-II)

A series of new polymetallic complexes have been prepared which couple d(6) pseudooctahedral light-absorbing centers to a d(8) square planar platinum site. These systems have lowest lying excited states that are M ---> BL charge transfer in nature. Hence, optical excitation directs charge flow toward the coupled platinum site. Synthetic Variation of the light-absorbing metal and the bridging ligand has been quite useful in the interpretation of the spectroscopic and electrochemical properties of these systems.