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Herein, we propose a strategically designed chalcone based donor\u2010acceptor system, where intensification of delayed fluorescence with decrease in temperature (300\u2005K to 100\u2005K) is observed; the theoretical investigations of electronic states and orbital characters uncovered a new cold rISC pathway in donor\u2010acceptor system, where rISC occurs through the down\u2010conversation of higher triplet exciton (from T<jats:sub>3<\/jats:sub>) to lowest singlet state (S<jats:sub>1<\/jats:sub>), having negative energy splitting, thus no thermal energy is required. The comprehensive research described herein might open\u2010up new avenues in donor\u2010acceptor system over the conventional up\u2010convention of triplet exciton and demonstrates that not necessarily all delayed fluorescence are thermally activated (TADF).<\/jats:p>","DOI":"10.1002\/chem.202302587","type":"journal-article","created":{"date-parts":[[2023,9,25]],"date-time":"2023-09-25T10:29:47Z","timestamp":1695637787000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Achieving the Reverse Intersystem Crossing in Chalcone Based Donor\u2010Acceptor System through Down\u2010Conversion of Triplet Exciton"],"prefix":"10.1002","volume":"29","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6409-2627","authenticated-orcid":false,"given":"Piyush","family":"Singh","sequence":"first","affiliation":[{"name":"Department of Chemistry Visvesvaraya National Institute of Technology  Nagpur 440010, Maharashtra 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