Molecular orbital PM3 calculation was performed on the complexation of cyclobis(para-quat-p-phenylene) with a number of 1,4-disubstituted benzenes and biphenyl derivatives. A fair correlation was found between the PM3 calculated binding energies and the experimental ones, which enabled the PM3 calculation to predict the experimental binding energies for a number of important complexes. A good structure-activity relationship was also found between the PM3 calculated binding energies and the substituent molar refraction Rm and Hammett σ constants, indicating that the van der Waals force and the electronic interactions constituted the major driving forces for the complexation of cyclobis(paraquat-p-phenylene). Molecular orbital PM3 calculation was performed on the complexation of cyclobis (para-quat-p-phenylene) with a number of 1,4-disubstituted benzenes and biphenyl derivatives. A fair correlation was found between the PM3 calculated binding energies and the experimental ones, which enabled the PM3 calculation to predict the experimental binding energies for a number of important complexes. A good structure-activity relationship was also found between the PM3 calculated binding energies and the molar molar refraction Rm and Hammett σ constants, indicating that the van der Waals force and the electronic interactions constituted the major driving forces for the complexation of cyclobis (paraquat-p-phenylene).