Abstract. Some novel spiropiperidinyl thiadiazolines have been synthesized and their bacterial activity against Streptococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Klepsiella pneumoniae and antifungal activity against Cryptococcus neoformans, Candida-6, Candida-51, Aspergillus niger and Aspergillus flavus were evaluated. Compound 23 exhibited potent antibacterial activity in vitro against ...