Given　the　high　similarity　in　physical　and　chemical　properties,　especially　in　terms　of　molecular　size　and　boiling　point,　of　acetylene　(C2H2),　carbon　dioxide　(CO2),　and　ethylene　(C2H4)　molecules,　traditional　separation　techniques　encounter　great　challenges.　Fortunately,　metal　organic　framework　(MOF)　materials　have　demonstrated　significant　potential　for　efficient　separation　of　these　gases　at　the　molecular　level　due　to　their　finely　tunable　pore　structure　and　surface　functional　properties.　In　this　paper,　we　have　successfully　synthesized　a　cadmium-based　MOF　(FJI-W-708),　which　exhibits　negative　electrostatic　potential　pores　and　exceptional　thermal　stability.　It　is　worth　noting　that　FJI-W-708　exhibits　high　C2H2　capacity　(61　cm3/g),　as　well　as　appropriate　selectivity　towards　C2H2/CO2　(3.39)　and　C2H2/C2H4　(3.47).　The　dynamic　breakthrough　experiments　of　C2H2/CO2　(50/50)　mixture　and　C2H2/C2H4　(1/99)　mixture　clearly　demonstrated　the　actual　separation　performance.　The　breakthrough　time　for　C2H2/CO2　(50/50)　was　observed　to　be　23　min/g,　while　for　a　C2H2/C2H4　(1/99)　mixture　it　could　reach　up　46　min/g,　demonstrating　excellent　recyclability　and　achieving　a　benchmark　productivity　of　C2H4　at　4.12　mmol/g.　©　2025　Wiley-VCH　GmbH.