Different substituted methoxy- and hydroxy-4-thioisosteres of flavonoids were prepared and their in vitro antimycotic activity towards yeast (Candida spp., Clavispora spp., Cryptococcus spp., Filobasidiella spp., Issatchenkia spp., Pichia spp., Kluyveromyces spp., Saccharomyces spp. and Yarrowia spp.) and yeast-like (Prototheca spp.) microorganisms was tested. Further insights in the biological activities of these antioxidant, oestrogenic and antimicrobial biomimetic derivatives were obtained.