An eco-friendly one-step preparation of various substituted 2-cyanobenzothiazole by condensation of corresponding substituted ortho-aminothiophenol with ethyl cyanoformate, employing an effective amount of Lawesson's reagent, under microwave irradiation (MWI) and solvent free conditions is presented. The structures of the compounds were elucidated with the aid of elemental analysis, IR, 1 H-NMR and mass spectral data. The targeted various substituted 2-cyanobenzothiazole are obtained in good yields and high purity.