We report a new concept of using conjugated polyfluorene imidazolium ionic liquids (PILs) intercalated reduced graphene oxide for high performance supercapacitor electrode materials. Two polyfluorene homo-polymer (hoPIL) and co-polymer (co-PIL) carrying hexyl imidazolium bromide side chains were designed and synthesized. Their corresponding intercalated reduced graphene oxide materials hoPIL-RGO and coPIL-RGO exhibited good electrochemical performance in aqueous electrolytes as well as in ionic liquid electrolyte 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4). High specific capacitances of 222Fg−1 at a current density of 0.2Ag−1 and 132Fg−1 at 0.5Ag−1 were obtained for coPIL-RGO in 6M KOH and BMIMBF4 accordingly. When assembled into a symmetric two-electrode cell with graphene materials as electrodes and BMIMBF4/acetonitrile (1:1) as electrolyte, an energy density of 14.7Whkg−1 was obtained for coPIL-RGO at a current density of 0.5Ag−1, and a maximum power density of 347kWkg−1 was achieved for hoPIL-RGO at a current density of 5Ag−1 with good cycling stability.