Homochiral Birefringence Hydrogen‐Bonded Organic Framework Films for Highly Circularly Polarized Luminescence

ABSTRACT Development of homochiral hydrogen‐bonded organic framework (HOF) film for highly circularly polarized luminescent (CPL) remains a significant challenge. In this study, we aim to construct HOF materials that integrate strong CPL with high chiral ordered structure through rational molecular design and supramolecular self‐assembly. We designed a homochiral HOF from enantiomeric 1,1′‐binaphthyl‐2,2′‐dihydroxy‐5,5′‐dicarboxylic acid (H 2 BDA), termed CAS‐10, which crystallize in the C222 1 space group, and realized its self‐organization into a highly oriented film through with in situ growth strategy. Our findings reveal that the oriented HOF film displays, strong chirality and intense blue luminescence, obvious CPL performance. By strategically incorporating linear birefringence effects, the g lum values reach an exceptional value of ±0.5 at 460 nm, representing a 167 times enhancement over the precursor disordered chiral molecule. This work not only presents an effective supramolecular assembly strategy for dramatically amplifying CPL performance through hydrogen‐bonded networks, but also pioneers the introduction of birefringence into chiral crystalline film materials. Furthermore, these advances establish a new material platform and design principle for developing cost‐effective, high‐performance CPL devices with practical applicability.