Cooperative Nitrogen Sites and Aromatic Pockets in a Dual‐Ligand MOF Enable Bifunctional Methane Purification

ABSTRACT Methane purification from coal‐bed methane and natural gas presents a persistent challenge in energy applications, yet materials capable of addressing both separations remain scarce. Here we report a rational ligand design strategy employing multi‐nitrogen sites and aromatic moieties to construct Zn‐ad‐ina , a metal–organic framework that combines exceptionally high CH 4 /N 2 selectivity with remarkable hydrocarbon/CH 4 discrimination. The material exhibits a substantial C 3 H 8 uptake of 74.3 cm 3 g −1 at 298 K and 1 bar, coupled with IAST selectivities reaching 936.3, 38.6, and 8.7 for C 3 H 8 /CH 4 , C 2 H 6 /CH 4 , and CH 4 /N 2 , respectively. GCMC simulations reveal a synergistic adsorption mechanism wherein nitrogen sites preferentially capture CH 4 over N 2 , while aromatic rings provide strong binding pockets for C 3 H 8 and C 2 H 6 . Hirshfeld surface analysis quantifies the framework‐adsorbate interaction landscape, and fixed‐bed breakthrough measurements demonstrate efficient recovery of high‐purity methane from both binary and ternary feed mixtures. This work establishes ligand‐directed functional site integration as a viable approach for engineering multifunctional adsorbents within unified framework architectures.