Diels–Alder Reaction of 1,3-Diarylbenzo[<i>c</i>]furans with Thiophene <i>S,S</i>-Dioxide/Indenone Derivatives: A Facile Preparation of Substituted Dibenzothiophene <i>S,S</i>-Dioxides and Fluorenones

One pot syntheses of substituted dibenzothiophene S,S-dioxides and fluorenones were successfully achieved by Diels–Alder reaction of benzo­[c]­furans with thiophene S,S-dioxides and indenones, respectively. Photophysical properties of representative seven- and nine-membered dibenzothiophene S,S-dioxide acenes were also reported.