Multi-resonance thermally activated delayed fluorescence emitters based on BNCz framework

positions relative to the boron atom. Specific strategies include introducing acceptor or donor groups to enhance intersystem crossing or achieve color tuning, modulating steric hindrance to mitigate aggregation-caused quenching, and incorporating chiral groups to induce circularly polarized emission. This review categorizes these substituents based on their structural characteristics and systematically discusses their impacts on the photophysical properties of the BNCz core and the overall performance of OLED devices, thereby providing critical insights for the design and future application of OLED materials.