Nucleophilic reactions of two 2,2'-bisbenzimidazole systems, namely the bis
(2H-benzimidazole-2-ylidene) 2 and the dispiro[2H-benzimidazole-2,1'-cycloh
exane-4',2 "-2 " H-benzimidazole] 3, as well as the syntheses of new 2,2'-b
isbenzimidazoles are reported and their conversion into other heterocycles
is described.