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These molecular systems can be converted between four states in response to light, acid, base, and heat. Quantitative conversion to higher energy metastable quadricyclane (QC) photoisomers is achieved upon UV irradiation, with photoisomerization quantum yields of 37% and 24% for <jats:bold>NBD 1<\/jats:bold> and <jats:bold>2<\/jats:bold>. The thermal half\u2010lives, <jats:italic>t<\/jats:italic><jats:sub>1\/2<\/jats:sub>, of 70 and 205\u2009days greatly surpass those of previously reported pyridine\u2010functionalized norbornadiene switches, as well as other acceptor\u2013acceptor systems. In particular, the <jats:italic>ortho<\/jats:italic>\u2010positioning of the pyridine has a profound effect on the half\u2010life; <jats:bold>QC 2<\/jats:bold> in its unprotonated form has the longest <jats:italic>t<\/jats:italic><jats:sub>1\/2<\/jats:sub> of 205\u2009days, while protonation to <jats:bold>QCH<\/jats:bold><jats:sup><jats:bold>+<\/jats:bold><\/jats:sup> <jats:bold>2<\/jats:bold> completely hinders the thermal back conversion, allowing energy to be stored in this state indefinitely. The stored energy can then be released as required upon the addition of a base, followed by thermal reversion to <jats:bold>NBD 2<\/jats:bold>. The energy storage densities are 162 and 393\u2009kJ\u2009kg<jats:sup>\u22121<\/jats:sup> for <jats:bold>NBD 1<\/jats:bold> and <jats:bold>NBD 2<\/jats:bold>, respectively. This approach of multimodal photoswitches can be applied to molecular solar thermal energy storage devices to enable long\u2010term energy storage and on\u2010demand controlled release.<\/jats:p>","DOI":"10.1002\/cssc.202501005","type":"journal-article","created":{"date-parts":[[2025,8,19]],"date-time":"2025-08-19T11:51:43Z","timestamp":1755604303000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Norbornadiene Quadricyclane as Multimode Photoswitches: Synergistic Light and Protonation\u2010Controlled Heat Release"],"prefix":"10.1002","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2498-3526","authenticated-orcid":false,"given":"Adil S.","family":"Aslam","sequence":"first","affiliation":[{"name":"Department of Chemistry and Chemical Engineering Chalmers University of Technology  41296 Gothenburg Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-5530-6263","authenticated-orcid":false,"given":"Monika","family":"Shamsabadi","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Chemical Engineering Chalmers University of Technology  41296 Gothenburg Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2213-6956","authenticated-orcid":false,"given":"Rebecca J.","family":"Salthouse","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering Universitat Polit\u00e8cnica de Catalunya (EEBE)  Eduard Maristany 10\u201314 08019 Barcelona Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4695-7943","authenticated-orcid":false,"given":"Joakim","family":"Andr\u00e9asson","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Chemical Engineering Chalmers University of Technology  41296 Gothenburg Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4018-4927","authenticated-orcid":false,"given":"Kasper","family":"Moth\u2010Poulsen","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Chemical Engineering Chalmers University of Technology  41296 Gothenburg Sweden"},{"name":"Department of Chemical Engineering Universitat Polit\u00e8cnica de Catalunya (EEBE)  Eduard Maristany 10\u201314 08019 Barcelona Spain"},{"name":"The Institute of Materials Science of Barcelona ICMAB\u2010CSIC  Bellaterra 08193 Barcelona Spain"},{"name":"Catalan Institution for Research &amp; Advanced Studies (ICREA)  Pg. 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