Many conventional thermally-driven separation processes can be replaced by pressure-driven membrane separation processes, possibly leading to substantial energy savings. However, the separation C2H4/C2H6 remains challenging owing to their marginal size difference. In this presentation, I will discuss a new approach for the solution-based in-situ synthesis of multivariate zeolitic imidazolate frameworks (ZIFs), referred to as Sogang ZIF-8 (SZIF-8) for enhanced C2H4/C2H6 kinetic separation. SZIF-8 nanoparticles comprise three different metal-ligand coordinate bonds in the framework, including Zn-2-methylimidazole, Zn-2,4-dimethylimidazole, and Zn-tributylamine. I will discuss the main role of multivariate ligands in the framework and the C2H4/C2H6 separation performance of the resultant mixed matrix membranes.