The electronic coupling in the electron transfer of the U-shaped anion model systems has been investigated in detail. Both the two-state model and Koopmans' theorem are employed to evaluate the electronic coupling. It is found that the total coupling is dominated by the through-space coupling, and the presence of a bridge partially cancels the through-space coupling. In order to investigate the solvent effect that facilitates the electronic coupling through the low-lying excited state of the aromatic solvent, a benzene molecule is adopted to mimic the solvent molecule and related discussions have been made. (c) 2005 Elsevier B.V. All rights reserved.