Novel substituted 4H-chromenes were synthesized via O-alkylation of 2-amino-7-hydroxy-4-phenyl-4H-chromene-3- carbonitrile (1) followed by hydrazinolysis to give the hydrazide 3. This key intermediate 3 was reacted with aromatic aldehydes, arylmethylenemalononitriles and substituted isothiocyanates to yield compounds 4a&b and 5a&b, respectively. In addition, cyclization of 5a&b in piperidine yielded the target thiazolo derivatives 6a&b. All newly synthesized compounds were evaluated for their in vitro antioxidant activity. Compound 5a was found to be the most potent antioxidant and the least active among the series being compound 1.