A series of π-conjugated alternating copolymers consisting of Th-ITN-Th and p-C6H2(OR)2 units were synthesized. XRD indicated that the copolymers assume an interdigitation packing mode, and UV-Vis spectra revealed a strong tendency for self-assembly. Upon molecular assembly of the copolymer, the UV-Vis absorption shifted by about 100 nm to a longer wavelength from that of the single molecule. The copolymers underwent electrochemical oxidation (or p-doping) and reduction (or n-doping) at 0.2 and −2.0 V versus Ag+/Ag, respectively. A p-doped copolymer film showed an electrical conductivity of 182 S · cm−1, and the temperature dependence of electrical conductivity was measured. The copolymer showed piezochromism and served as a p-channel material for a field-effect transistor.