Condensation of ethyl 3-formyl-1H-indole-2-carboxylate (1) with thiosemicarbazide in ethanol gave ethyl 3-(thiosemicarbazidomethyl)-1H-indole-2-carboxylate (2). Treatment of 2 with chloroacetic acid afforded the thiazolidin-4-one derivative 3. Condensation of 3 with aromatic aldehydes gave the corresponding arylidene derivatives 4a-c. Cyclization of 4a-c with hydroxylamine hydrochloride in the presence of sodium acetate yielded thiazolidino[4,5-c]isoxazoline derivatives 5a-c. The structure of the synthesized compounds were confirmed using elemental and spectroscopic analysis.