A cooperative experimental/modeling strategy was used to unveil the structure/gas separation performance relationship for a series of isostructural metal-organic frameworks (MOFs) with soc-topology (square-octahedral) hosting different extra-framework counter ions (NO₃ ^-, Cl^- and Br^-). In³⁺-, Fe3⁺-, Ga³⁺- and the newly isolated Al(iii)-based isostructural soc-MOF were extensively studied and evaluated for the separation-based production of high-quality fuels (i.e., CH₄, C₃H₈ and n-C₄H₁₀) and olefins. The structural/chemical fine-tuning of the soc-MOF platform promoted equilibrium-based selectivity toward C₂₊ (C₂H₆, C₂H₄, C₃H₆ C₃H₈ and n-C₄H₁₀) and conferred the desired chemical stability toward H₂S. The noted dual chemical stability and gas/vapor selectivity, which have rarely been reported for equilibrium-based separation agents, are essential for the production of high-purity H₂, CH₄ and C₂₊ fractions in high yields. Interestingly, the evaluated soc-MOF analogues exhibited high selectivity for C₂H₄, C₃H₆ and n-C₄H₁₀. In particular, the Fe, Ga and Al analogues presented relatively enhanced C2+/CH4 adsorption selectivities. Notably, the Ga and Al analogues were found to be technically preferable because their structural integrities and separation performances were maintained upon exposure to H₂S, indicating that these materials are highly tolerant to H₂S. Therefore, the Ga-soc-MOF was further examined for the selective adsorption of H₂S in the presence of CO₂- and CH₄-containing streams, such as refinery-off gases (ROG) and natural gas (NG). Grand canonical Monte Carlo (GCMC) simulations based on a specific force field describing the interactions between the guest molecules and the Ga sites supported and confirmed the considerably higher affinity of the Ga-soc-MOF for C₂+ (as exemplified by n-C₄H₁₀) than for CH₄. The careful selection of an appropriate metal for the trinuclear inorganic molecular building block (MBB), i.e., a Ga metal center, imbues the soc-MOF platform with the requisite hydrolytic stability, H₂S stability, and exceptional gas selectivity for ROG and NG upgrading. Finally, the soc-MOF was deployed as a continuous film on a porous support, and its gas permeation properties as a membrane were evaluated.