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-2$H$-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/NH$_{4}$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-2$H$-chromen-7-yl)oxy)phenyl)carbamothioyl)benzamide (7l) showed the best activity as potent as the reference drug, quercetin.