The C-60 complex with decamethylcobaltocene, (Cp*Co-2)(2)C-60(C6H4Cl2, C6H5CN)(2) (1) (C6H4Cl2 = 1,2-dichlorobenzene; C6H5CN = benzonitrile), has been obtained as single crystals by the diffusion method. The IR and UV-vis-NIR spectra show the presence of the C-60(2-) and the Cp*Co-2(+) ions, which form a three-dimensional framework with channels accommodating solvent molecules. EPR and SQUID measurements show that C602- has a diamagnetic singlet (S = 0) state in the 2-140 K range. The appearance of a broad EPR signal and the increase in magnetic susceptibility of 1 above 140 K are assigned to a thermal population of a close lying triplet (S = 1) state. The singlet-triplet energy gap for C602- in solid 1 is estimated to be 730 +/- 10 cm(-1).