Abstract: One-pot and facile preparation of novel 2-(4H-4-oxo-benzopyran-3-yl)benzothiazolium salts 3 is described using the fast condensation of 3-formylchromones 1 with 3-benzyl-2-methylbenzothiazolium (or benzoxazolium) bromides 2. Reactions under microwave irradiation, in comparison with classical reactions, proceeded significantly faster and with high yields. Reaction of benzothiazolium salts with secondary and primary amines was also studied. Synthesized chromone derivatives stimulated significantly the growth of the radicle and the hypocotyl at concentrations of 0.1 and 1 ppm, respectively.