We demonstrate high-efficiency red electrophosphorescent organic light-emitting devices employing bis(2-(2′-benzo[4,5-a]thienyl)pyridinato-N,C3′) iridium(acetylacetonate) [Btp2Ir(acac)] as a red phosphor. A maximum external quantum efficiency of ηext = (7.0±0.5)% and power efficiency of ηp = (4.6±0.5) lm/W are achieved at a current density of J = 0.01 mA/cm2. At a higher current density of J = 100 mA/cm2, ηext = (2.5±0.3)% and ηp = (0.56±0.05) lm/W are obtained. The electroluminescent spectrum has a maximum at a wavelength of λmax = 616 nm with additional intensity peaks at λsub = 670 and 745 nm. The Commission Internationale de L’Eclairage coordinates of (x = 0.68, y = 0.32) are close to meeting video display standards. The short phosphorescence lifetime (∼4 μs) of Btp2Ir(acac) leads to a significant improvement in ηext at high currents as compared to the previously reported red phosphor, 2,3,7,8,12,13,17,18-octaethyl-12H, 23H-prophine platinum (II) PtOEP with a lifetime of ∼50 μs. © 2001 American Institute of Physics.