Charge Transfer Modulated Salicylaldehyde Hydrazone‐Based N,O,O‐Chelated Boron Complexes With Aggregation‐Induced Emission and Large Stokes Shifts

We report a compact N,O,O‐chelated tetracoordinate boron platform (BSBHYs) assembled by a modular one‐pot strategy that independently varies the aldehyde and boronic‐acid components while embedding a strong dimethylamino donor to enhance charge transfer (CT) modulation. Remarkably, these boron chelates achieve an uncommon combination of large Stokes shifts (>3000 cm −1 ) and pronounced aggregation‐induced emission (AIE). Spectroscopic measurements and density functional theory calculations reveal that the distorted N,O,O coordination geometry promotes a CT‐modulated emissive state and substantial excited‐state relaxation, accounting for the large Stokes shifts, whereas the AIE turn‐on arises from restriction of intramolecular rotation in the condensed phase, which suppresses motion‐assisted nonradiative decay. The calculations further connect donor–acceptor orbital separation with oscillator strength, identify an optically allowed higher singlet state feeding emission via internal conversion, and indicate minimal intersystem crossing. This work establishes a structure–motion–electronic‐state framework for emission control in N,O,O‐boron luminogens.