Orthogonal Postsynthetic Copolymerization of Hydrogen‐Bonded Organic Frameworks into a PolyHOF Membrane

Abstract Hydrogen‐bonded organic frameworks (HOFs) have shown promise in various fields; however, the construction of HOF/polymer hybrid membranes that can maintain both structural and functional integrity remains challenging. In this study, we here fabricated a new HOF ( HOF‐50 ) with reserved polymerizable allyl group via charge‐assisted H‐bonds between the carboxylate anion and amidinium, and subsequently copolymerized the HOF with monomers to construct a covalently bonded HOF/polymer hybrid (polyHOF) membrane. The resulting polyHOF membrane not only exhibits customizable mechanical properties and extreme stability, but also shows an exceptional ratiometric luminescent temperature‐sensing function with very high sensitivity and visibility even when the lanthanide content is two orders of magnitude lower than that of the reported mixed‐lanthanide metal–organic frameworks (MOFs) and lanthanide‐doped covalent organic frameworks (COFs). This orthogonal postsynthesis copolymerization strategy may provide a general approach for preparing covalently connected HOF/polymer hybrid membranes for diverse applications.