A new procedure, which enables us to decompose the solvent reorganization energy into electrostatic and nonelectrostatic contributions, is proposed. By using the procedure proposed by us very recently (J. Phys. Chem. A 2002, 106, 2300-2304), the solvent reorganization process and electronic structures of N,Ndimethylaniline (DMA) and 1,4-dimethoxybenzene (DMB) associated with a charging process in acetonitrile solution are studied at the molecular level on the basis of the ab initio reference interaction site model-selfconsistent field (RISM-SCF) method. Differences as well as similarities between the solvation processes of the two molecules are discussed on the basis of the newly proposed method.