The excited triplet states of phthalic anhydride and its chlorinated derivatives in methyl substituted benzene derivatives were studied at 77 K by a time-resolved EPR technique. The increase of the number of the methyl group on the benzene decreased the zero-field splitting parameters of their triplet states. This was explained by the contribution of the electron-donor-acceptor (EDA) complex. Especially, in the case of tetrachlorophthalic anhydride in hexamethylbenzene, the apparent inversion of the spin-polarization was observed. These data evidenced the negative sign of the D value in highly charge-transferred (CT) complex. This experiment reveals that the employment of D value instead of D* provides much better estimation of the CT character of the EDA complex.