A series of 2,3-C2B3-bridged iron-cobalt and dicobalt triple-decker complexes having Cp or Cp* end rings was examined in detail via several techniques, including correlated H-1 and C-13 NMR spectra, which allow complete assignment of the resonances of paramagnetic species. The 29 valence electron (ve) complexes Cp*Fe(Et(2)C(2)B(3)H(2)-5-R)CoCp* (1a, R = H; 1b, R = Cl; 1c, R = Br) were prepared from nido-Cp*Co(Et(2)C(2)B(3)H(4)-5-R) by bridge-deprotonation and treatment with (Cp*FeCl)(2) and examined by cyclic voltammetry, ESR, and Mossbauer spectra and NMR correlation experiments. In the latter studies, paramagnetic neutral species were progressively reduced to the diamagnetic monoanions 1a(-)-1c(-) via repeated contact with a potassium mirror in the NMR tube or oxidized to the diamagnetic cations by treatment with AgBF4. The data consistently support a model in which the unpaired electron in the neutral species 1a is primarily associated with Fe; in the paramagnetic 31 ve dianion 1a(2-), the unpaired electron resides mainly on cobalt. Correlated H-1 and C-13 NMR studies on the mixed-ligand 29 ve FeCo complex Cp*Fe(Et(2)C(2)B(3)H(3))CoCp (2) and the diamagnetic 30 ve dicobalt complexes Cp*Co(R’2C2B3H3)COCP* (3a, R’ = Et; 3b, R’ = Me; 3c, R’ = H) and Cp*Co(Et(2)C(2)B(3)H(3))CoCp (4), together with their associated cationic and anionic species, afforded additional information on the electronic structures of these systems. The preparation and spectroscopic characterization of the new complexes 1a-1c, 2, 3a, and 3a(-) are reported, as well as X-ray crystal structure determinations on a K(THF)(crown ether)(+) salt of 3a(-) acid neutral 4. Crystal data for [K(THF)(crown ether)(+)][3a(-)] : Co2KO7C42B3H75, space group P2(1)2(1)2(1) (orthorhombic); a = 15.252(14), b = 15.54(2), c = 20.25(2) Angstrom; Z = 4; R = 0.046 for 6641 independent reflections. Crystal data for 4 : Co2C21B3H33, space group P2(1)/c (monoclinic); a = 8.694(4), b = 21.049(11), c = 11.870(8) Angstrom; beta = 101.15(4) Angstrom; Z = 4; R = 0.039 for 4653 independent reflections.