Three dinuclear complexes were prepared in which Cr(CO)(2)(PPh(3)) moieties are connected through biphenyl linkages. The dihedral (twist) angle of the two arenes in the biphenyl decreases from 100 to 17 to 0 degrees as the bridging ligand is changed from biphenyl-2,2’-dicarboxylic acid dimethyl ester (in compound 2) to dihydrophenanthrene (3) to fluorene (4). All three compounds are oxidized in two reversible one-electron steps with a voltage separation of ca. 260 mV. Each monocation is shown by IR spectroscopy to be trapped-valent. ESR spectroscopy in frozen glasses gives the same result. IR sampling of the dications is achieved by low-temperature flow electrochemical experiments. The asymmetric stretching frequency of the CO pair assigned to the Cr(0) site in the mixed-valent ion is measurably shifted from that of the original (CrCr0)-Cr-0 complex, and the amount of shift increases significantly as the biphenyl twist diminishes. It is proposed that although the half-filled orbital is localized on one metal site in the monocations, there is significant transmission of charge between the metals through fined orbitals of the biphenyl linkage. The results support a through-space model for electronic (mixed-valent) delocalization in Cr-I(mu-biphenyl)Cr-0 linkages. Results of studies of the oxidation of (arene)Cr(CO)(2)L, where L = CO or PPh(3), and of (biarene)Cr-2(CO)(6), prepared as part of this work, are briefly reported.