Aggregated-state arylborane-pillar[5]arenes: a new three-in-one method for the modulation of circularly polarized luminescence

Although chiroptical macrocyclic systems are highly studied in supramolecular chemistry and materials science, it remains a substantial challenge to simultaneously achieve high emission efficiency and a strong circularly polarized luminescence (CPL) dissymmetry factor. Herein, we report a molecular design strategy that integrates aggregation-induced emission (AIE), heteroatom incorporation, and symmetry engineering to modulate the chiroptical performance of planar chiral pillar[5]arene luminogens. In these modular chiral systems of arylborane-pillar[5]arenes (1–4) functionalized with classical tetraphenylethylene (TPE) and BN-isostere tetraarylaminoborane (BN-TPE), the heteroatom-regulated excited-state electronic structures and BN dipole-induced symmetry perturbation are synergistically coupled with AIE-active emissions, enabling the simultaneous enhancement of fluorescence efficiency and CPL performance. Compared with the carbon-based parent 1, both 2 and 4 exhibit highly enhanced chiroptical properties with an aggregated-state emission quantum yields (Φ_F) of up to 96% and B_CPL values of up to 43.4 M⁻¹ cm⁻¹. Experimental and theoretical studies reveal that triarylborane incorporation promotes excited-state charge separation and AIE-enhanced fluorescence, whereas BN substitution introduces symmetry perturbation and electronic polarization that facilitate efficient chiroptical emissions. The three-in-one strategy established in this work may open new opportunities to close the persistent gap between emission efficiency and chiroptical activity, and highlights the potential of heteroatom-engineered chiral macrocycles for advanced functional materials and in optoelectronic applications.