Tailor‐Made Chromophore Ligands Enable High‐Performance Near‐Infrared Emissive Iridium Complexes Beyond 900 nm With Maximum EQE of 1.42%

ABSTRACT Developing high‐performance near‐infrared (NIR) emitting Ir(III) complexes beyond 900 nm remains a formidable challenge due to the energy gap law and related processing issues. Herein, we develop three novel NIR Ir(III) complexes, (pqx) 2 Iracac (1) , (pqx)Ir(ppy) 2 (2) , and (pqx‐BT)Ir(ppy) 2 (3) , featuring tailor‐made conjugation‐extended CˆN chromophore ligands based on 6,8‐di‐ tert ‐butylpyrido[3,4‐ b ]quinoxaline (pqx) . Complex (pqx) 2 Iracac shows intensive NIR emission with peak wavelength at 865 nm in toluene and 840 nm with a maximum external quantum efficiency (EQE max ) of 2.08% in OLED devices. Complexes (pqx)Ir(ppy) 2 and (pqx‐BT)Ir(ppy) 2 both bear a single chromophore ligand with two ancillary phenylpyridine (ppy) ligands, yielding desired advantages of reduced chromophore consumption, streamlined synthesis, lowered molecular weight for enhanced processability, and design flexibility. In particular, the introduction of an electron‐rich benzo[ b ]thiophene (BT) group as the anionic carbon‐coordinating part (C‐part) of complex (pqx‐BT)Ir(ppy) 2 achieves a large redshift of the emission peak to 933 nm in toluene. The corresponding solution‐processed NIR‐OLEDs based on complex (pqx‐BT)Ir(ppy) 2 enable an emission peak at 908 nm with an EQE max of 1.42%, breaking the 900 nm threshold for Ir(III)‐based NIR‐OLEDs. This work establishes a molecular design blueprint for the development of high‐efficiency pure NIR organic emitters for various applications.