The electronic structures of cyclic-polyindenoindenes (PInIn) and their derivatives have been studied by restricted Harlxee-Fock at AMI level. The substituent effect is discussed also. The calculated results show that these polymers are semiconductors, and although the band gap decreases for most of the substituted derivatives of polyindenoindenes, the polymers can not be conductors in intrinsic state by the substitution. Electron affinity of the substituted PMns chain is raised due to the substitution of electron-withdrawing substituents, while the ionization potential is decreased by electron- donating substituents. Therefore, the substitution of electron-donating group is favorable to p-type doping, while the substitution of electron-withdrawing group to n-type doping. In addition, one of cyclic-polyindenoindenes is a high-spin polymer and might become a magnetic material. Neither the electron-donating group nor the electron-withdrawing group can alter the magnetism of cyclic- polyindenoindene.

Key words: CYCLIC COMPOUNDS, POLYMER, INDENE P, ELECTRONIC STRUCTURE, SEMICONDUCTOR, MAGNETISM, SUBSTITUENT EFFECT