New iridium complexes that have carbonyl group were synthesized and demonstrated various red light emission in organic light-emitting diodes (OLEDs). The maximum luminance of 57000~15300 cd/m2 at 15v and the luminance efficiency of 22.8~ 5.6 cd/A at 20 mA/cm2 WERE ACHIEVED RESPECTIVELY. the peak wavelength of the electroluminescence were at 570~604 nm and the device also showed a stable color chromaticity with various voltages.