True-blue Ir(III) phosphors are designed, synthesized, and applied to multilayered organic true-blue-light-emitting diodes with CIEx,y color chromaticity of (0.15,0.11) and maximum external quantum efficiency of similar to 12%, demonstrating unprecedented performance among all blue-phosphorescent OLEDs ever documented. The molecular-design strategy and subsequent device-fabrication protocol reveal a major development in OLEDs.