The 1:1 charge transfer salt of dimethyltetrathiotetracene (DMTTT) and of tetracyanoethylene (TCNE), C26H12N4S4 crystallizes from chlorobenzene in the monoclinic system, space group P2(l)/c with cell constants a = 11.136(2), b = 11.254(3), C = 17.280(4) A, beta = 96.56(2), V = 2151.4(9) A, Z = 4 and dcalc = 1.57 0 mg/nun. The structure is made up of dimers of DMTTT and TCNE, respectively. Polycrystalline samples of DMTTT/TCNE exhibit a weak paramagnetism which was studied by ESR techniques from 102 to 293 K. The ESR studies reveal anisotropie spectra which are best resolved in the temperature range 102 to 250 K. The spectra observed are those expected from a spin system which is described by an orthorhombic g-tensor. The isotropie g-value calculated from the observed anisotropie g-tensors falls between the isotropie g-values for DMTTT and TCNE. As the temperature is increased, the spectral width decreases suggesting motion of and/or an increase in the spin concentration. DMTTT/TCNE is a relatively poor electrical conductor which is consistent with its crystal structure.