Sorting of C₄ Olefins with Interpenetrated Hybrid Ultramicroporous Materials by Combining Molecular Recognition and Size‐Sieving

C 4 olefin separations present one of the great challenges in hydrocarbon purifications owing to their similar structures, thus a single separation mechanism often met with limited success. Herein we report a series of anion‐pillared interpenetrated copper coordination for which the cavity and functional site disposition can be varied in 0.2 Å scale increments by altering the anion pillars and organic linkers (GeFSIX‐2‐Cu‐i (ZU‐32), NbFSIX‐2‐Cu‐i (ZU‐52), GeFSIX‐14‐Cu‐i (ZU‐33)), which enable selective recognition of different C 4 olefins. In these materials the rotation of the organic linkers is controlled to create a contracted flexible pore window that enables the size‐exclusion of specific C 4 olefins, while still adsorbing significant amounts of 1,3‐butadiene (C 4 H 6 ) or 1‐butene (n‐C 4 H 8 ). Combining the molecular recognition and size‐sieving effect, these materials unexpectedly realized the sieving of C 4 H 6 /n‐C 4 H 8 , C 4 H 6 /iso‐C 4 H 8 , and n‐C 4 H 8 /iso‐C 4 H 8 with high capacity.