2-amino-6-chloro-benzothiazole on microwave irradiation in the presence of 1-butyl-3-methylimidazolium and inorganic anions yields fluorinated benzothiazolo[2,3-b]quinazoline-2H-ones analogues. It has synergistic effect on inhibitive performance of propargyl alcohol during corrosion of mild steel in boiling HCl solution.