• • mer-Ir(Bpmb)3 achieves a maximum external quantum efficiency (EQE) of 20.0% in OLEDs, with current efficiency (CE) of 70.8 cd A−1 and power efficiency (PE) of 92.6 lm W−1, demonstrating superior device performance for green phosphorescent emitters.
• • The rigid BO-fused ring design elevates the MLCT character to 21.69% (mer-Ir(Bpmi)3) and 17.30% (mer-Ir(Bpmb)3), compared to 13.01% and 15.99% for reference complexes, enhancing spin-orbit coupling and radiative transitions.
• • Both complexes exhibit high thermal stability with decomposition temperatures of 491°C (mer-Ir(Bpmi)3) and 540°C (mer-Ir(Bpmb)3), ensuring robustness for vacuum thermal evaporation in OLED manufacturing.
• • Short phosphorescence lifetimes (846 ns for mer-Ir(Bpmi)3; 1083 ns for mer-Ir(Bpmb)3) and high radiative rate constants (10.04 × 10^5 s−1 and 7.29 × 10^5 s−1) reduce efficiency roll-off at high brightness, critical for display applications.