Great　attention　has　been　attracted　to　the　salicylaldehyde　Schiff　base　due　to　its　thermochromic　and　photochromic　characteristics　in　the　solid　state.　However,　the　boundary　between　photochromic　and　thermochromic　salicylaldehyde　Schiff　base　structures　is　still　unclear,　and　few　studies　have　been　conducted　to　investigate　their　thermochromic　behavior　and　structures　in　depth　and　systematically.　In　the　present　work,　we　have　synthesized　a　novel　salicylaldehyde　Schiff　base　derivative　(2,2′-((1E,1′E)-((2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diyl)-bis(azaneylylidene))bis(methaneylylidene))diphenol,　BTB)　with　twisted　structure,　which　possesses　both　thermochromic　and　aggregation-induced　emission　(AIE)　characteristics,　and　systematically　investigated　its　thermochromic　properties,　enol-keto　isomerization,　AIE　properties,　aggregated　state,　and　excited　state　intramolecular　proton　transfer　(ESIPT)　process.　Interestingly,　in　our　study,　we　found　that　the　color　of　the　BTB　molecule　changed　gradually　during　the　heating　process,　and　it　can　be　found　that　the　thermochromism　of　BTB　is　produced　by　the　reversible　equilibrium　shift　of　the　enol　form　and　the　keto　forms　due　to　the　temperature　change　by　the　color　difference　test,　the　in-situ　IR　spectra　and　the　DSC　curves.　Finally,　the　pathway　of　BTB　proton　transfer　was　analyzed　through　quantum　chemical　calculations,　and　it　was　found　that　enol　ketone　isomerization　is　achieved　through　single　excited　state　intramolecular　proton　transfer,　rather　than　the　expected　double　excited　state　intramolecular　proton　transfer.　©　2024　Elsevier　B.V.