Giant Circularly Polarized Luminescence Driven by Excited‐State Hybridization Between Molecular Emitters and Chiral Environments

Abstract Circularly polarized (CP) light is extensively used in various fields such as asymmetrical synthesis, sensing, and advanced displays. Consequently, significant efforts have been made to develop chiral materials that intrinsically emit CP light with a large dissymmetry factor ( g ‐factor). It is widely considered that the dissymmetry factor for individual organic emitters, due to the amplitude offset between their electric and magnetic transition dipole moments, is limited to ≈10 −2 , which is inadequate for practical applications. Recent efforts to enhance CP light emission have therefore focused on amplifying the dissymmetry of circularly polarized luminescence (CPL), often via specific energy transfer processes. Here, a fundamental mechanism is discovered – excited‐state hybridization, which amplifies CPL through excitonic coupling without relying on energy transfer processes. Through this wavefunction hybridization, both the amplitude and sign of the rotatory strength related to the molecular emitter's electronic transition are modified to align with its chiral environment, remarkably boosting the CP luminescence from an intrinsic dissymmetry factor of −10 −3 up to +0.40. This breakthrough allows for more versatile design strategies for chiral emissive systems, moving beyond designs limited to energy transfer processes and paving the way for new approaches to achieve strong CP emissive materials.