Zero-dimensional　(0D)　organic-inorganic　hybrid　metal　halides　have　attracted　significant　attention　for　optoelectronic　applications,　yet　zinc-based　systems　remain　underexplored　due　to　limited　structural　diversity　and　low　photoluminescence　quantum　yields　(PLQYs).　Here,　we　report　a　novel　0D　hybrid,　(MTP)(2)ZnBr4　(MTP　=　methyltriphenylphosphonium),　which　exhibits　green　luminescence　originating　from　the　radiative　complexation　of　self-trapped　excitons　(STEs)　with　a　PLQY　of　38.6　%,　outperforming　existing　zinc-based　hybrid　halide　systems.　This　remarkable　efficiency　stems　from　the　rigidity-enhanced　suppression　of　non-radiative　composite　pathways.　The　(MTP)(2)ZnBr4　exhibits　thermally　activated　exciton　localization　phenomenon:　at　higher　temperatures　(＞　240　K),　the　material　exhibits　only　a　single　emission　peak　at　517　nm;　at　low　temperatures,　a　distinct　dual-emission　characteristic　emerges　with　the　appearance　of　a　new　emission　peak　at　480　nm　either.　This　paper　provides　a　new　example　of　a　temperature-modulated　material　with　potential　applications　in　solid-state　lighting　and　temperature-responsive　optoelectronic　devices.