Using copolymerization functionalization, poly[3,4-dioctyloxythiophene-alt-2,5-bis(4-vinylphenyl)-1,3,4-oxadiazole] (P3,4DOOTV-OXD) combining electrochemical properties of poly(3,4-dioctyloxythiophene) (P3,4DOOT, donor) and 1,3,4-oxadiazole (OXD, acceptor) was synthesized through Heck reaction and evaluated with (1)H-NMR, FTIR, gel permeation chromatography (GPC), UV-vis spectroscopy, photoluminescence (PL), and electroluminescence (EL) spectra. This D/A alternating copolymer, with regio-symmetrical 3,4-dioctyloxythiophene, has good solubility in common organic solvents. The optical properties investigations showed that the band-gap energy of P3,4DOOTV-OXD is 10% higher than that of P3,4DOOT (2.27 eV) at 2.52 eV in solid film. However, the photoluminescence (PL) quantum yield is as high as 57.4%, > two times more than that of homopolymer P3,4DOOT in CHCl(3) solution, and displays bright green-yellow luminescence (518 nm) in solution and yellow (542 nm) in solid film. Cyclic voltammogram indicated that the copolymer has bipolar properties, and the band gap energy (E(g)) calculated based on the cyclic voltammogram is consistent with that deduced from the absorption spectra at 2.40 eV. By using indium-tin oxide (ITO) as the anode, poly(ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) as the hole-injection layer, P3,4DOOTV-OXD as the emitter and aluminum (Al) as the cathode, double-layer device with the structure of [ITO/PEDOT: PSS (50 nm)/polymer/Al (130 nm)] shows typical diode characters and exhibit bright yellow electroluminescence (562-552 nm) under the forward bias. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 50-54, 2011