A Near‐Infrared‐II Emissive Chromium(III) Complex

The combination of π-donating amido with π-accepting pyridine coordination units in a tridentate chelate ligand causes strong nephelauxetic effect homoleptic CrIII complex, which shifts its luminescence to the NIR-II spectral range. Previously explored polypyridine complexes typically emit between 727 and 778 nm (in red NIR-I region), design strategies have so far concentrated on optimizing field strength. present work takes fundamentally different approach focusses increasing metal–ligand bond covalence shift ruby-like 2E emission 1067 at 77 K.