Novel derivatives of chromenone bearing an N-carbamothioyl moiety were synthesized and evaluated for their soybean 15-LOX inhibitory activity. Synthesis of the target compounds was started from 7-hydroxy-2H-chromen-2-one. It was reacted with 1-fluoro-2(4)-nitrobenzene to obtain the corresponding nitrophenoxy-chromenone derivative. Reduction of the nitro group was achieved in the presence of Zn/NH4 Cl and reaction of the latter compound with in situ prepared benzoyl isothiocyanate led to the formation of the title compounds. All compounds were characterized and tested against soybean 15-LOX. Among them, 4-methyl-N-((4-((2-oxo-2H-chromen-7-yl)oxy)phenyl)carbamothioyl)benzamide (71) showed the best activity as potent as the reference drug, quercetin.