Poly(biphenylenevinylene-alt-2-methoxy-5-octyloxy-1,4-phenylene-vinylene) (PBPV-alt-MOPPV) has been designed and synthesized by Wittig polymerization. Structure, thermal stability, optical, and electrochemical properties of the resulting copolymer were characterized by FT-IR, H-1 NMR, elemental analysis, GPC, DSC, TGA, UV-Vis, PL, EL, and CV. The copolymer possessed excellent solubility in common organic solvents and good thermal stability. The absorption maxima of copolymer in solution and thin film were at 440 and 450 nm, the PL maxima in solution and thin film were at 510 and 550 nm. The PLED (ITO/PEDOT: PSS (40 nm)/polymer (80 nm)/Ca (30 nm)/Al (150 nm) showed a yellowgreen light emission around 530 nm. The maximum brightness and luminescence efficiency reached up to 1,450 cd m(-2), 0.12 cd A(-1), and 0.06 lm w(-1), respectively.