The synthesis of BEDT-TTF, bis(ethylenedithio)-tetrathiafulvalene, charge transfer salts with isostructural magnetic and non-magnetic anions M(C2O4)3(3-), where M(III) is Cr, Co, Al is reported. (BEDT-TTF)(4)[Cr(C2O4)(3)]. C6H5CN is a semiconductor(sigma(RT) 1-10 Scm(-1), E(A)=0.09 eV). The EPR spectrum is characterised by one single resonance with a g-value average between those of BEDT-TTF radical and Cr3+. The linewidth is exchange narrowed. The temperature dependence of the susceptibility indicates antiferromagnetic interactions. Infrared data give an optical gap (similar to 0.2eV) which is consistent with that obtained by the electrical measurement.