As continuation of the studies on the synthesis and evaluation of biologically active compounds functionalized by 2,4-dihydroxyphenyl substituent, a series of N-modified thiobenzamides have been prepared. They have been obtained by the reaction of the corresponding amines with the electrophilic thioacylating agent. The compounds have been subjected to in vitro antifungal activity screening against phytopathogenic fungi and antiproliferative potency against human cancer cell lines. N-(2,1,3-Benzothiadiazol-5-yl)-2,4-dihydroxybenzothioamide exhibits the highest antifungal activity, especially against R. solani and P. cactorum. 2,4-Dihydroxy-N'-(3-methyl-1,3-benzothiazol-2(3H)-ilidene)benzothiohydrazide shows high antiproliferative potency against the SW707 cells at IC50 = 2 μM, similar to that of cisplatin. To explain differences in the activity of the compounds, their in silico properties have been estimated.