AbstractThe condensation of 2,5,6‐benzimidazolinetrione with ethylenediamine resulted in the formation of the 1,3‐dihydro‐2H‐imidazo[4,5‐g]quinoxalin‐2‐one ring system. The reaction of this trione with excess ethanethiol resulted in the isolation of three hydroquinones which were oxidized to the respective quinones. 2,4,7‐Benzimidazolinetrione was shown to undergo a Diels‐Alder reaction with isoprene and a mono‐addition reactio