Ion　doping　has　been　demonstrated　as　a　practical　approach　to　achieving　highly　efficient　luminescence　in　both　inorganic　phosphors　and　organic-inorganic　hybrids.　The　as-formed　doping　species　show　great　potential　in　optoelectronic　applications　due　to　their　high　photoluminescence　quantum　yield　(PLQY)　and　excellent　stability.　Herein,　we　report　highly　emissive　Sb3+-doped　indium　halides　(C6H18N2)InCl5·H2O:Sb　(C6H18N22+　=　N,N,N′,N′-tetramethylethane-1,2-diammonium)　prepared　by　solution　evaporation　methods　with　an　emission　that　peaked　at　565　nm　and　a　PLQY　of　74.6%.　Photophysical　characterizations　and　density　functional　theory　computational　studies　verify　the　broadband　emission　originating　from　a　self-trapped　exciton.　Interestingly,　a　drastic　red　shift　of　the　emission　peak　from　565　to　663　nm　with　yellow　luminescence　turning　to　red　is　observed　once　the　(C6H18N2)InCl5·H2O:Sb　hybrid　is　exposed　to　methanol　vapor.　Moreover,　when　the　methanol-exposed　hybrid　is　put　in　air,　the　emission　reverts　to　565　nm　in　several　minutes.　Single-crystal　X-ray　diffraction　studies　show　a　subsequent　structure　distortion　upon　the　coordination　of　methanol　to　the　Sb(III)　center,　which　is　responsible　for　the　drastic　red　shift　of　the　emission.　Encouragingly,　we　found　that　(C6H18N2)InCl5·H2O:Sb　exhibits　a　specific　response　to　methanol　vapor　after　screening　a　series　of　volatile　organic　compounds　with　different　polarities.　Besides,　a　negligible　change　of　the　emission　intensity　is　observed　after　several　cycles　of　uptaking　and　releasing　methanol.　The　high　fatigue　resistance　and　specific　solvent　response　of　the　Sb3+-doped　indium　halide　make　it　a　very　promising　methanol　detector.　[Figure　not　available:　see　fulltext.].　©　2022,　Science　China　Press　and　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.