Herein we report that readily available 4‐alkenylisocoumarins can be regarded as potent dienolate equivalents. For example, lactol silyl ethers derived from 4‐alkenylisocoumarins were selectively converted to the corresponding benzo‐homophthalates through a fluoride‐induced ring opening step that was followed by a ring closure through a vinylogous intramolecular aldol condensation. Likewise, nucleophilic activation of 4‐alkenylisocoumarins directly yields diversely poly‐substituted naphthalenes and anthracenes without formation of any regioisomer. Photophysical evaluation of a set of thus obtained 1,3‐di‐ and 1,3,4‐trisubstituted anthracenes reveals their distinct intramolecular charge transfer (ICT) character during light absorption in polar solutions and excimer emission from the solid state when a face‐to‐face π‐stacked molecular assembly is present in the crystal packing.
