The molecular structures of thermally structurized polyacrylonitrile (PAN), that is, polypyridinopyridine (PPyPy) series have been investigated by using quantum chemistry semiem-pirical MNDO, CNDO/2-CO methods. The changing regularities of structural stability and electronic properties are pointed out. The analyses of the energy band structures indicate that the energy gaps will become smaller, intrinsical conductivities will increase when the quasi-one-dimentional (1D) series of PPyPy molecule widen toward two-dimention (2D), which is consistent with the experimental results of polymerization degree (PD) and electrical conductivity increase with the increasing of pyrolyzed temperature. The molecular structures of thermally structured polyacrylonitrile (PAN), that is, polypyridinopyridine (PPyPy) series have been investigated by using quantum chemistry semiem-pirical MNDO, CNDO / 2-CO methods. The changing regularities of structural stability and electronic properties are pointed out . The analyzes of the energy band structures indicate that the energy gaps will become smaller, intrinsical conductivities will increase when the quasi-one-dimentional (1D) series of PPyPy molecule widen toward two-dimention (2D), which is consistent with the experimental results of polymerization degree (PD) and electrical conductivity increase with the increasing of pyrolyzed temperature.