2-Chloro-5-nitrobenzaldehyde undergoes condensation reaction with 2-methyl-1-propenylbenzimidazole to yield (E,Z)-2-(2-chloro-5-nitrostyryl)-1-(1-propenyl)benzimidazole. It reacts with 5-aminopyrazoles to yield symmetrical bispyrazolo[3,4-]pyridines.