New ionic DA-type charge transfer solids of C-70(-) were prepared with bis(benzene)chromium (Bz(2)Cr) and decamethylinetallocenes (Cp-2*M) (M = Ni, Cr). In the solid-state EPR spectra, no signals confirming C-70(-) Spins were detected below room temperature (RT), probably due to either an electronic or chemical dimerization. Above RT, a signal characteristic of a strong exchange coupling between donor cation and C-70(-) spins gradually emerged for Bz(2)Cr complex, owing to the decoupling of the dimers. In dimethyl sulfoxide at RT, a signal characteristic of C-70(-) spins was observed at g = 2.0012-2.0014 with a narrow linewidth. (C) 2002 Elsevier Science B.V. All rights reserved.