Excited-state conformational flexibility enables intrinsic amplification of circularly polarized luminescence.

Achieving intrinsic amplification of circularly polarized luminescence (CPL) through excited-state conformational regulation remains a fundamental challenge in chiral photonic materials. Here, we demonstrate that excited-state conformational flexibility enables intrinsic CPL amplification in supramolecular polymers. A conformationally adaptable luminophore is integrated into a hydrogen-bonded chiral supramolecular polymer, where photoinduced conformational planarization modulates the local intermolecular environment and organization of emissive units. This conformational adaptability enhances chiroptical responses without relying on external photophysical amplification effects. A 35-fold amplification of CPL is achieved, which significantly exceeds the increase in total emission intensity, suggesting that the enhancement originates from intrinsic chiroptical regulation rather than simple brightness modulation. Control experiments and computational analyses reveal that molecular conformational flexibility and supramolecular organization are critical for the photoactivated CPL amplification. These findings establish excited-state conformational flexibility as a molecular design principle for intrinsically photoresponsive chiroptical materials.