2-Aryl-1-arylmethyl-1 H-benzimidazoles are prepared in high yields under extremely mild conditions via the condensation of aryl-1, 2-diamines with aromatic aldehydes using 10 mol% of bismuth triflate in water. The use of water and readily available bismuth triflate makes this process quite simple, more convenient, and environment-friendly. Key words: aryl-1, 2-diamines, aromatic aldehydes, bismuth catalysis, benzimidazoles.