Fourier transform EPR spectroscopy was employed in studying the electron transfer (ET) and the quenching mechanisms of the photoexcited triplet state of C-60 (electron donor) in the presence of the electron acceptor tetracyanoethylene (TCNE) in a benzonitrile solution. The ET reaction product, which is the stable anion radical TCNE-, interacts with C-3(60) (both detected by EPR in the liquid phase), leading to chemically induced dynamic electron polarization of TCNE-, via triplet-doublet mixing mechanism.