6/6,7-Substituted-3-formylchromones (8a-g) were reacted with 2 equivalents thiobenzamide (9) in refluxing toluene to furnish substituted-3-(5-phenyl-3H-[1,2,4]dithiazol-3-yl)chromen-4-ones (10a-g) in high yields. Similarly, when substituted-2-anilino-3-formylchromones (8a-d) were reacted with thiobenzamide (9, 2 equivalents) in refluxing xylene, 4-oxo-4H-chromene-3-carbothioic acid N-phenylamides (11a-d) were obtained in high yields. All the compounds (10a-g) and (11a-d) display significant cytotoxic activity against a number of human cancer cell lines. Among these compounds 10e (IC(50) = 10 microM), 10b (IC(50) = 14.6 microM) and 10a (IC(50) = 10.5 microM) showed maximum cytotoxic activity on neuroblastoma. Also, the compound 10c (IC(50) = 10.5 microM) showed maximum cytotoxic activity on ovarian cancer cell line.