A series of 4-(alkylidene/arylidene)amino-5-(2-furanyl)-2,4-dihydro- 3H-1,2,4-triazole-3-thiones (2) and 6-aryl-3-(2-furanyl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines (3) were synthesized. The configuration of 2g was assigned on the basis of 1H-NMR data. Of the new derivatives tested, only 2b, 2g, and 4f were found to be active against Staphylococcus aureus and/or Staphylococcus epidermidis (MIC 125-1.95 micrograms/ml), whereas all exhibited varying degrees of antifungal activity (MIC 25-0.8 micrograms/ml).