Indolocarbazole (ICz)‐Centered Expanded Di[7]Helicenes for High‐Performance Narrowband Red Emission and Circularly Polarized Luminescence

ABSTRACT Helicenes, known for their helical π ‐conjugated structures and pronounced chiroptical properties, hold great promise for optoelectronic and photonic applications. However, simultaneously enhancing their configurational stability, emission efficiency, and chiral luminescence remains a synthetic challenge. Herein, we introduce an indolo[3,2,1‐jk]carbazole (ICz) core incorporation strategy to construct two structurally defined, expanded helicenes: rac‐1 and meso‐1 . This strategy, when synergistically combined with π ‐extension via aromatic fusion, significantly improves molecular rigidity, suppresses non‐radiative decay, and enhances photophysical and chiroptical performance. Structural analysis confirms that both compounds adopt well‐defined helical architectures with high configurational stability. Remarkably, rac‐1 exhibits narrowband red fluorescence (full width at half maximum (FWHM) = 16–20 nm), a high quantum yield ( Φ _F = 0.54), and good circularly polarized luminescence (| g _lum | = 1.17 × 10 ⁻³ ; B _CPL = 66.6 M ⁻¹ cm ⁻¹ ), outperforming previous analogs. Both helicenes also show excellent resistance to protonation, oxidation, and thermal racemization. These results underscore the power of the ICz core incorporation design in stabilizing the helicene framework and unlocking new levels of optical and chiral performance, offering a versatile platform for next‐generation functional chiral materials.