Several novel Schiff base macrocyclic compounds of Thiotriazinone were synthesized from cyanuric chloride, diethylamine p-nitrophenol, 1,2-dibromoethane, salicylaldehyde, p-hydroxybenzaldehyde, vanillin and isovanillin by high dilution method, and their structures were characterized by IR, 1H NMR and ESI/MS techniques. The studies on the UV-Vis absorption spectroscopies show that Schiff base 5 have a selective recognition for Fe3+.