In the search for new agents with estrogenic activity mediated by estrogen receptors (ER), six 6, 12-dihydro-1-benzopyrano [3, 4-b][1, 4] benzothiazin-6-ones 3a–f were synthesized. These compounds were readily prepared by the addition of 2-aminothiophenol 2 to substituted 4-hydroxycoumarin derivatives 1a–e. The estrogenic effect has been evaluated on the proliferation of MCF-7 breast adenocarcinoma cells and the specificity of described ...