Two-dimensional　(2D)　materials,　in　particular　emerging　2D　layered　hybrid　perovskites,　have　manifested　excellent　potential　for　polarization-sensitive　photodetection　recently　due　to　their　highly　intrinsic　anisotropy,　characteristic　quantum-well　structure　and　intriguing　semiconducting　properties.　However,　most　of　the　reported　2D　hybrid　perovskites　still　suffer　from　limited　crystal　dimensions　or　narrow　spectral　photoresponse　to　the　polarized　light.　Herein,　we　have　developed　a　new　layered　iodide　perovskite　(s-BA)2(MA)Pb2I7(1,　s-BA+is　sec-butylammonium　and　MA+is　methylammonium)　through　symmetry-reduction　and　halide　remolding,　which　exhibits　highly　structural　anisotropy　and　a　narrow　bandgap　of　2.02　eV.　Strikingly,　centimeter-sized　crystals　with　dimensions　up　to　19　×　19　×　3　mm3can　be　obtainedviatemperature　cooling　method.　Based　on　such　large　crystals,　photodetectors　were　fabricated　which　manifest　impressive　response　to　polarized　light　with　a　large　dichroism　ratio　of　about　1.16,　notable　responsivity　of　97.22　mA　W−1and　considerable　detectivity　of　2.79　×　1011Jones.　This　work　offers　a　new　candidate　to　the　further　exploration　of　highly　anisotropic　hybrid　perovskites　for　extended　spectral　polarization-sensitive　photodetection.　©　The　Royal　Society　of　Chemistry　2021.