Synergistic High-Connectivity and Nonplanar Conformation Generates a Stable Hydrogen-Bonded Organic Framework for Benchmark Methanol-to-Olefin Product Separation.

Hydrogen-bonded organic frameworks (HOFs) are promising porous materials, yet their development is hindered by an inherent trade-off between structural stability and functional site accessibility. Conventional stabilization strategies relying on extensive π-π stacking inevitably shield aromatic surfaces, compromising adsorption performance. Herein, we report a synergistic design strategy that integrates high hydrogen-bonding connectivity with inherently nonplanar molecular conformations to overcome this challenge. The strategically designed tetraisophthalate linker, featuring a hexamethylbiphenyl core, adopts a nonplanar conformation that suppresses extended π-π stacking, while its eight carboxylic acid groups form a dense hydrogen-bonded network ensuring framework robustness. The resulting HOF-ZJNU-10 exhibits a high BET surface area (2500 m2 g-1), exceptional stability, and crucially, fully accessible aromatic surfaces lining the pore channels. This unique combination enables outstanding methanol-to-olefins (MTO) product purification, delivering polymer-grade ethylene and propylene with record-high productivity. This work establishes a general blueprint for decoupling stability from functional site masking in HOFs.