Two-dimensional　hybrid　perovskite　(2DHPs)　semiconductors　have　shown　great　potential　in　multifunctional　applications,　especially　dielectric　switches　and　photoelectric　detection　owing　to　their　diverse　structural　feasibility　and　excellent　semiconducting　features.　However,　most　of　the　reported　2DHPs　belong　to　the　Ruddlesden-Popper　(R-P)　type,　which　unavoidably　suffers　from　weak　van　der　Waals　interactions,　degrading　their　reliability　for　long-term　operation.　The　recently　developed　environmentally　stable　Dion-Jacobson　(D-J)　phase　perovskites　provide　us　with　an　opportunity　to　design　2DHPs　with　durable　working　performances.　Here,　we　report　a　D-J　phase　perovskite　material　(BDA)MA2Pb3Br10　(1,　where　BDA2+　is　1,4-butanediammomium　and　MA+　is　methylammonium)　that　displays　a　remarkable　switchable　dielectric　anomaly　at　322　K.　Meanwhile,　the　single　crystal　devices　of　1　exhibit　impressive　photoelectric　detection　performances,　featuring　a　large　on/off　current　ratio　(∼6.19　×　103),　remarkable　responsivity　(∼11.79　mA　W−1),　and　high　detectivity　(∼2.9　×　1011　Jones).　Additionally,　due　to　the　phase　stability　conferred　by　the　D-J　structure,　these　devices　exhibit　excellent　photoresponsivity　and　resistance　to　fatigue,　as　evidenced　by　over　1200　photoresponse　cycles,　along　with　noteworthy　stability　in　dielectric　switching　(maintained　for　two　months).　This　study　presents　a　comprehensive　methodology　for　designing　highly　stable　D-J　phase　perovskites　with　exceptional　performance　in　dielectric　switching　and　photoelectric　detection,　thereby　expanding　the　repertoire　of　2D　D-J　multifunctional　hybrid　perovskites.　©　2024　The　Royal　Society　of　Chemistry.