A combination of biotechnological and electrochemical techniques is employed to synthesize an electroactive pi-conjugated polymer. The monomer precursor bearing a hydroxyl group is obtained by the bioconversion of dibenzothiophene. An alkyl chain substituent is introduced by Williamson etherification with the aid of crown ether, and electrochemical polymerization is carried out by repeated potential scanning of the monomer in an electrolytic reaction solution. The polymer film thus prepared is shown to exhibit good electroactive characteristics.