The increasing clinical importance of drug-resistant bacterial pathogens has lent additional urgency to microbiological and antibacterial research. New indolic derivatives of triazoles, thiadiazoles and their respective open-chain thiosemicarbazides were evaluated for antibacterial and antifungal activity. The microorganisms used were the Gram-negative bacteria Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 27853, the Gram-positive bacteria Staphylococcus aureus ATCC 25923 and Bacillus subtilis BBL 12084 and the yeasts Candida and Saccharomyces cerevisiae ATCC 2366. The most potent compounds were indole derivatives (12a-c) bearing 1,2,4-triazo-thien-5-yl moiety, which exhibit interesting antibacterial and antifungal activities.