Precise Molecular Sieving of n‐hexane From C6 Isomers Utilizing a Vanadium‐Squarate Framework

High‐purity n‐hexane (nHEX) is a critical industrial feedstock, but conventional distillation often yields low purity due to contamination by structurally similar C6 isomers and cyclic impurities. Current methods, such as energy‐intensive fractional distillation or 5A zeolite‐based adsorption, suffer from high cost, large energy demand, and limited capacity and selectivity, especially at industrially relevant temperatures (≥423 K). While metal–organic frameworks (MOFs) offer promise, existing variants typically lack the pore precision needed to separate nHEX from mono‐branched isomers and degrade in performance at elevated temperatures. Here, we report USTC‐742, a vanadium‐squarate MOF with ultramicroporous, precisely engineered pores that enable highly selective nHEX separation via molecular sieving. It delivers excellent performance across 303–423 K: at 423 K, its nHEX uptake reaches 141 mg g −1 , over 50% higher than 5A zeolite, demonstrating superior selectivity. Breakthrough experiments confirm consistent >99.99% nHEX purity. Coupled with thermal stability, techno‐economic viability, and robust performance in shaped forms, USTC‐742 is a strong candidate for scalable high‐purity nHEX production. This work sets a new benchmark for hydrocarbon separation sorbents under practical conditions.