a novel p-n diblock copolymer constituted of 2,2'-bipyridylene vinylene and 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene moieties was synthesized and characterized, The electrochemical properties of the copolymer were evaluated and the HOMO and LUMO energy levels of the polymer were estimated by cyclic voltammetry. The polymer demonstrated intrinsically balanced tendencies for injecting and transporting electrons and holes, which are essential for fabrication of Light-emitting diodes. (C) 2001 Elsevier Science Ltd. All rights reserved.