Hydrogen purification is a critical challenge for clean energy. The Sun and Kang’s group have now developed a novel composite membrane using a "mortar-and-brick" strategy. This membrane combines a metal-organic framework (MOF) as the "bricks" with a hydrogen-bonded organic framework (HOF) as the "mortar," creating an all-nanoporous hierarchical structure. Hetero-MOF facilitates the hetero-nucleation, and the systematic rule of HOF’s crystal growth interfered by hetero-phase is established: suppressing the homo-nucleation, balancing nucleation driving force with molecular attachment rates, and optimizing the nutrients supplement and demand. The optimized membrane shows a 562% increase in hydrogen permeance and 241% improve in hydrogen/methane selectivity compared to a pure HOF membrane, offering a new blueprint for next-generation gas separation materials that combine easy processing with high performance.