A simple and convenient method for synthesizing dipyrido[1,2-a:1′2′-a′]benzo[1,2-d:5,4-d]diimidazole-6,13-dione

Reduction of 1,1'-(4,6-dinitro-1,3-phenylene)dipyridinium dichloride with SnCl2 afforded dipyrido[1,2-a:1',2'-a']benzo-[1,2-d:5,4-d]diimidazole which was converted into the corresponding quinone-type 6,13-dione in three simple steps.