Unveiling a Quinoidal 2,3:10,11-Dibenzoheptazethrene.

Parent 2,3:10,11-dibenzoheptazethrene is a singlet diradicaloid polycyclic hydrocarbon in the ground state that did not change its diradical character upon substitution (methyl and triisopropylsilylethynyl). Described herein are the synthesis and characterization of an ethoxy/3,5-(CF 3 ) 2 C 6 H 3 -substituted 2,3:10,11-dibenzoheptazethrene 3 that prefers to retain its p -quinoidal core and shows zero diradical character, as determined by single-crystal analysis and density functional theory calculations. Negative solvatochromism, π-π interactions, C sp 2 -H···O hydrogen bonding, intramolecular charge transfer, redox amphotericity, and a narrow HOMO-LUMO energy gap make 3 a potential candidate for application in optoelectronics.