The　efficient　capture　of　fluorinated　gases　(F-gases)　such　as　hexafluoroethane　(R116)　and　1,1,1,2-tetrafluoroethane　(R134a)　is　critical　owing　to　the　high　global　warming　potential　of　these　species.　Considering　the　potential　of　ionic　liquids　(ILs),　especially　fluorinated　ILs　(FILs),　for　capturing　F-gases,　in　this　study　we　systematically　investigated　the　structure-property　relationship　between　thermodynamic　behaviors　and　weak　interactions　in　F-gas/FIL　systems.　We　focused　on　two　cations,　1-octyl-3methylimidazolium　([OMIM](+))　and　1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)-3-methylimidazolium　([FOMIM](+)),　and　two　anions,　bis(trifluoromethylsulfonyl)amide　([Tf2N])　and　bis(pentafluoroethylsulfo　nyl)amide　([BETI]).　The　effects　of　the　IL　structure　on　the　gas-liquid　equilibrium　(GLE)　of　F-gas/FIL　systems　were　elucidated　by　analyzing　the　experimental　solubility　data.　The　results　indicate　that　while　both　the　fluorinated　cation　and　anion　can　enhance　the　solubility　of　F-gases,　the　contribution　of　the　fluorinated　cation　to　the　increase　in　solubility　is　larger　than　that　of　the　fluorinated　anion.　The　relationship　between　GLE　behavior　and　weak　interactions　of　F-gas/FIL　systems　was　determined　by　performing　quantum　chemical　calculations.　(C)　2021　Elsevier　Ltd.　All　rights　reserved.