A Deep‐Blue Emitting Macrocyclic Digold(I) Complex Supported by a Bridging Multiresonance Ligand

A dinuclear macrocyclic gold(I) complex, namely 5CAuBN , is developed by bridging a multiple‐resonance (MR) boron/nitrogen (B/N) framework with a bis‐nitrogen‐heterocyclic carbene (NHC) through dual coordination. How the coordination position and cyclic architecture modulate the photophysical properties has been investigated. It exhibits an efficient deep‐blue thermally activated delayed fluorescence (TADF) with a photoluminescence quantum yield of 0.83 and a delayed fluorescence lifetime of 6.02 μs. A minor contribution of Au 5 d orbitals to the frontier molecular orbitals is proven crucial for enhancing the spin–orbit coupling (SOC) effect with the narrowband emission preserved.