A novel copolymer, poly[9-(4'-tert-butyl-phenylenemethene)-fluoroene-co-9,9-dioctylfluorene ], has been synthesized through the Yamamoto coupling method. The copolymer has good solubility and thermal stability with a glass transition temperature at 85 degrees C. The PL spectrum of the copolymer shows a maximum emission peak at 530 nm. A polymer light-emitting diode (PLED) with the configuration ITO/PEDOT/copolymer/Ca/Al has been fabricated. The device emits green light with an emission peak at 540 nm. A maximum brightness of 603 cd/m(2) was achieved at a drive voltage of 24.3 V.