It is essential to create organic compounds that exhibit circularly polarized luminescence (CPL) in the near-infrared (NIR) range. Helicene-type emitters possess appealing chiroptical features, however, such NIR molecules are scarce due to a paucity of synthetic strategies. Herein, we developed a series of helical βisoindigo-based BÀ OÀ B bridged aza-BODIPY analogs that were synthesized conveniently. The reaction of diimino-β-isoindigo with a heteroaromatic amine produced a restricted ligand cavity, which triggered off the generation of a BÀ OÀ B bridge. The BÀ OÀ B bridge led to distorted conformations that satisfy the helical requirements, resulting in excellent spectroscopic and chiroptical properties. Tunable CPL with the highest luminescence dissymmetry factor (g lum ) of 1.3 × 10 À 3 and a CPL brightness (B CPL = 11.5 M À 1 cm À 1 ) in the NIR region was achieved. This synthetic approach is expected to offer a new opportunity to chiral chemistry and increase flexibility for chiroptical tuning.

It is essential to create organic compounds that exhibit circularly polarized luminescence (CPL) in the near-infrared (NIR) range. Helicene-type emitters possess appealing chiroptical features, however, such NIR molecules are scarce due to a paucity of synthetic strategies. Herein, we developed a series of helical βisoindigo-based BÀ OÀ B bridged aza-BODIPY analogs that were synthesized conveniently. The reaction of diimino-β-isoindigo with a heteroaromatic amine produced a restricted ligand cavity, which triggered off the generation of a BÀ OÀ B bridge. The BÀ OÀ B bridge led to distorted conformations that satisfy the helical requirements, resulting in excellent spectroscopic and chiroptical properties. Tunable CPL with the highest luminescence dissymmetry factor (g lum ) of 1.3 × 10 À 3 and a CPL brightness (B CPL = 11.5 M À 1 cm À 1 ) in the NIR region was achieved. This synthetic approach is expected to offer a new opportunity to chiral chemistry and increase flexibility for chiroptical tuning.