Introducing Functional Groups Into B←N Organic Frameworks with Permanent Porosity

Abstract Crystalline organic frameworks incorporating dative B←N and reversible B─O bonds (BNOFs) have garnered increasing interest on account of their crystallinity, porosity, and processability. However, strategies for introducing functions into BNOFs remain largely unexplored. In this work, a series of functionalized BNOFs, named BNOF‐ n ( n = 2–9), have been designed and synthesized using a mixed‐monomer assembly strategy. The obtained materials share structural similarities but reveal distinct functional groups, demonstrating excellent chemical stability, high surface areas, and remarkable regenerability. Notably, BNOF‐5, functionalized with abundant carboxyl groups, achieves exceptional reversible NH 3 adsorption capacity (up to 10.0 mmol g −1 at 1 bar and 298 K), significantly surpassing that of the nonfunctionalized BNOF‐1 (5.6 mmol g −1 ) and the less‐functionalized BNOF‐7 (7.9 mmol g −1 ), thereby clearly demonstrating the effectiveness of the functionalization strategy. Remarkably, the damaged BNOF‐5 can be efficiently repaired through facile regeneration, highlighting its outstanding recyclability. This work demonstrates the first attempt at functionalization methodology in BNOFs, extending their potential toward diverse applications.