Solar-driven　photothermal　chemical　transformations　are　regarded　as　green　processes　to　reduce　energy　consumption　and　are　expected　to　utilize　unique　light-induced　activation　mechanisms　to　improve　reaction　kinetics.　Halide　perovskites　and　their　derivatives,　due　to　unique　optoelectronic　properties　and　compositional　flexibility,　are　allowed　for　the　precise　regulation　of　energy　band　structures　and　surface　electronic　states,　showing　potentials　as　photoactivated　catalysts　with　photo-thermal　synergistic　effects.　However,　the　photothermal　catalytic　performance　of　halide　perovskites　is　still　unsatisfied　with　low　conversion　(＜0.2%).　Herein,　Cs3BixSb2-xBr9　is　designed　as　a　novel　and　effective　photothermal　catalyst　for　light-driven　degradation　of　ester　under　room　temperature,　achieving　a　near-unity　conversion　of　≈99%　without　external　heating.　Photothermal　catalytic　process　shows　the　remarkable　enhancementup　to　796%　and　200%　compared　with　that　in　the　single　thermocatalysis　or　photocatalysis.　The　stable　catalyst　shows　superior　light-driven　cyclic　performance,　as　well.　Mechanistic　studies　combined　with　in　situ　characterizations　and　theoretical　calculations　show　that　photon-bismuth　hotspot　with　the　synergy　of　photoinduced　charge　transfer　process　(photochemistry)　significantly　reduce　the　activation　energy,　light-to-heat　effects　(thermochemistry)　elevate　the　local　temperature,　and　bismuth　active　site　promotes　the　C─O　bond　activation　(surface　adsorption),　which　together　contribute　to　excellent　solar-driven　conversion　efficiency　on　the　perovskite　derivative.　©　2025　Wiley-VCH　GmbH.