N-[2-(1,3-dimethyl-1,3-dihydro-benzoimidazol-2-ylidene)-ethylidene]-aniline 、
1,3,5,7-tetraethyl-2,6-dimethyl-3,7-dihydro-benzo[1,2-d;4,5-d']diimidazolediium; bis-(toluene-4-sulfonate) 在
乙酸酐 作用下,
以37%的产率得到2,6-bis<3-(1,3-dimethylbenzimidazole-2(3H)-ylidene)-1-propenyl-1,3,5,7-tetraethylbenzo<1,2-d:4,5-d'>>diimidazolium diiodide