White polymeric light-emitting diode (WPLED) based on a single polymer, poly(3-hexylthiophene-alt-9,9-dioctylfluorene) (PTAF), has been successfully demonstrated. This conjugated alternating copolymer, PTAF, comprises 50 mol % of 3-hexylthiophene which is an orange-red color chromophore and 50 mol % 9,9-dioctylfluorene which is a bluish-green color chromophore. It was synthesized by Suzuki cross-coupling reaction and has a molecular weight of 15,021 and polydispersity of 1.36. Nanocomposite consisting PTAF and graphene nanosheets enhances the optoelectronic properties and the device fabricated with a configuration of ITO/PEDOT:PSS/(PTAF + 1% graphene)/Ca/Al shows two-color white electroluminescence with CIE 1931 coordinates of (0.28, 0.34). The white luminescence from a single polymer affords the WPLED device a simple structure and low fabrication cost. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011