C4 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 C4 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 C4 olefins, while still adsorbing significant amounts of 1,3‐butadiene (C4H6) or 1‐butene (n‐C4H8). Combining the molecular recognition and size‐sieving effect, these materials unexpectedly realized the sieving of C4H6/n‐C4H8, C4H6/iso‐C4H8, and n‐C4H8/iso‐C4H8 with high capacity.