A novel Ir complex, (BuPhNPPy)(2)Ir(acac) with arylamine unit, was synthesized. A peak external quantum efficiency of 10.4% photons per electron at current density of 32 mA/cm(2) and a maximum luminance of 14610 cd/m(2) at drive voltage of 24 V were achieved in a single-layered polymer light-emitting device using this Ir complex as dopant with 4% dopant concentration and a blend of poly(vinylcarbazole) as host matrix. The highly efficient electrophosphorescence of the Ir complex was exhibited with green emission at 533 nm.