A novel boron-stereogenic fluorophore with dual-state circular polarization luminescence via a self-dispersing...

Molecular engineering is a reliable approach for the development of circularly polarized luminescence (CPL) materials for various applications. However, creating dual-state CPL platforms that possess chirality while achieving a delicate balance between molecular rigidity and flexibility remains a formidable challenge. In this study, a novel bisarylboron-anchored pyrrolylsalicylhydrazone (BOPSH) platform was synthesized via a facile "one-pot" condensation. These key aryl-boron substituents not only provide structural rigidity to the fluorophore, enhancing the bright emission and suppressing emission quenching from π-π stacking in solid states due to their twisting and bulky steric effects, but also generate a boron-stereogenic center and enable strong CPL by promoting intramolecular charge-transfer transitions. As a result, these BOPSHs show intense absorption and strong dual-state emissions in both solution and solid states (with Φ _PL value approaching unity), emitting across the visible region with excellent chemical, photostability, and thermal stability. Meanwhile, their enantiomers display dual-state CPL performance, with luminescence dissymmetry factors (g _lum) up to 9.40 × 10^-3, and CP electroluminescence (EL) with a dissymmetry factor (g _EL) of 3.07 × 10^-3, along with excellent maximum external quantum efficiencies (η _ext,max) of 5.0%, approaching the theoretical limit for fluorescent molecules. We expect our study to break new ground in the construction of chiral dual-state materials with diverse structures.