Single-molecule　junctions　are　building　blocks　for　constructing　molecular　devices.　However,　intermolecular　interactions　like　winding　bring　additional　interference　among　the　surrounding　molecules,　which　inhibits　the　intrinsic　coherent　transport　through　single-molecule　junctions.　Here,　we　employed　a　nanocavity　(dimethoxypillar　[5]　arene,　DMP[5]),　which　is　analogous　to　electric　cables,　to　confine　the　conformation　of　flexible　chains　(1,8-diaminooctane,　DAO)　via　host-guest　interaction.　Single-molecule　conductance　measurements　indicate　that　the　conductance　of　DAO　encapsulated　with　DMP[5]　is　as　high　as　that　of　pure　DAO,　as　reproduced　by　theoretical　simulations.　Intriguingly,　the　molecular　lengths　of　the　DAO　encapsulated　with　DMP[5]　increase　from　1.13　nm　to　1.46　nm　compared　with　the　pure　DAO,　indicating　that　DMP[5]　keeps　DAO　upright-standing　via　the　confinement　effect.　This　work　provides　a　new　strategy　to　decouple　the　intermolecular　interaction　by　employing　an　insulating　sheath,　enabling　the　high-density　integration　of　single-molecule　devices.　(c)　2025　Published　by　Elsevier　B.V.　on　behalf　of　Chinese　Chemical　Society　and　Institute　of　Materia　Medica,　Chinese　Academy　of　Medical　Sciences.