2D　Ruddlesden-Popper　(RP)　polar　perovskite,　displaying　the　intrinsic　optical　anisotropy　and　structural　polarity,　has　a　fantastic　application　perspective　in　self-powered　polarized　light　detection.　However,　the　weak　van　der　Waals　interaction　between　the　organic　spacing　bilayers　is　insufficient　to　preserve　the　stability　of　RP-type　materials.　Hence,　it　is　of　great　significance　to　explore　new　stable　2D　RP-phase　candidates.　In　this　work,　we　have　successfully　constructed　a　highly-stable　polar　2D　perovskite,　(　t　-ACH)2　PbI4　(　1　,　where　t　-ACH+　is　HOOC8　H12　NH3　+　),　by　adopting　a　hydrophobic　carboxylate　trans　-isomer　of　tranexamic　acid　as　the　spacing　component.　Strikingly,　strong　O-H　O　hydrogen　bonds　between　t　-ACH+　organic　bilayers　compose　the　dimer,　thus　decreasing　van　der　Waals　gap　and　enhancing　structural　stability.　Besides,　such　orientational　hydrogen　bonds　contribute　to　the　formation　of　structural　polarity　and　generate　an　obvious　bulk　photovoltaic　effect　in　1　,　which　facilitates　its　self-powered　photodetection.　As　predicted,　the　combination　of　inherent　anisotropy　and　polarity　leads　to　self-powered　polarized-light　detection　with　a　high　ratio　of　around　similar　to　5.3,　superior　to　those　of　inorganic　2D　counterparts.　This　work　paves　a　potential　way　to　design　highly-stable　2D　perovskites　for　high-performance　optoelectronic　devices.　(c)　2025　Published　by　Elsevier　B.V.　on　behalf　of　Chinese　Chemical　Society　and　Institute　of　Materia　Medica,　Chinese　Academy　of　Medical　Sciences.