An　organic-inorganic　semiconducting　compound　of　1-methylpiperidinium　triiodoplumbate(ii)　(MPIP),　adopting　a　one-dimensional　ABX3　perovskite-like　structure,　has　been　synthesized.　It　is　notable　that　MPIP　undergoes　a　structural　phase　transition　(SPT)　at　Tc　≅　202　K,　as　confirmed　by　DSC　and　Cp　analyses.　Strikingly,　MPIP　exhibits　remarkable　switchable　dielectric　responses;　that　is,　the　distinct　step-like　anomalies　in　the　vicinity　of　Tc.　The　switching　between　high-dielectric　and　low-dielectric　states　makes　MPIP　a　potential　switchable　dielectric　material.　Single-crystal　structural　analysis　reveals　that　the　most　distinct　difference　between　its　high-temperature　phase　(above　Tc)　and　low-temperature　phase　(below　Tc)　is　the　order-disorder　transformation　of　a　1-methylpiperidinium　cation,　which　accounts　for　its　SPT　and　striking　dielectric　response.　Besides　this,　MPIP　shows　semiconducting　behaviour　with　an　optical　bandgap　of　∼2.48　eV,　comparable　to　some　other　lead-iodide　perovskites.　The　combination　of　semiconducting　and　dielectric　attributes　provides　a　new　perspective　for　the　design　of　hybrid　perovskites　as　multifunctional　materials.　©　the　Partner　Organisations　2018.