A series of 2-substituted benzimidazoles were prepared through one-pot reaction of o-phenylenediamine with various aryl aldehydes in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in acetonitrile as solvent at room temperature. The reactions were smoothly preceded in excellent yields and short reaction times with an easy work-up. The pure benzimidazoles as products were confirmed and characterized by physical and spectral data.