Photochemical behaviors of a tethered 1,3-diketone derivative studied by transient absorption and time-resolved EPR measurements

► Acetyltetralone has two candidates for the enol structure. ► The transient absorption and time-resolved EPR were measured. ► The formation of triplet acetyltetralone was recognized. ► The molecular structure of the enol form was endocyclic with the C-C double bond.