A general procedure for the preparation of mono-N-methyl anilines has been developed with excellent yields. This protocol relies on a NaBH3 (OAc) reduction of formimidate intermediates that are quantitatively generated by treatment of primary substituted anilines with triethyl orthoformate under the catalysis of MCM-41-SO3H mesoporous zeolite. The newly developed procedure was facile, efficient, and environmentally benign.