A novel ancillary ligand (2-(1-hydroxy-naphthyl)-benzothiozolato) (HNBT) and corresponding iridium(III) complex, Ir(ppy)(2)(NBT) (ppy = 2-phenylphridine) are synthesized, and red-emitting electrophosphorescent devices by doping Ir(ppy)(2)(NBT) in 4,4'-N,N'-dicarbazole-biphenyl (CBP) are fabricated. the optimized device displays EL spectrum with a narrow full-width at half-maximum of 65 nm, and the Comission International de L'Eclairage (CIE) coordinates of (0.65, 0.33) are very close to those suggested by the National Television System Committee (NSTC) standard for a red emitter. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3596543] All rights reserved.