IN AN one pot procedure 1,3- and 1,2-dicarbonyl compounds (ethyl cyanoacetate, ethyl acetoacetate, diethyl malonate, acetylacetone and oxalyl chloride) were reacted in different solvents with the readily available 2-amino-5-heptadecyl thiadiazole to produce novel polyfunctionalized thiadiazoles, fused thiadiazolo [3,2-
a] pyrimidines ,and imidazo [2,1-a]thiadiazole. The reaction of 2-amino-5-heptadecyl thiadiazole with triethylorthoformate, 2-naphthaldehyde, succinic anhydride, and hydroxylamine hydrochloride was also carried out. Moreover, the biological activities of the synthesized compounds were screened in vitro against some bacteria and fungi. Tetracycline was taken as a standard antibacterial agent and amphotericin B as a standard antifungal agent. It was reported that 3-amino-5-heptadecyl [1,2,4] triazol-4-ol showed very high activity against G- bacteria, while thiadiazolo [3,2-a] pyrimidines and imidazo [2,1-a] thiadiazole exhibited high activity against G+ bacteria. In addition structure-activity relationship (SAR) study was carried out. For industrial purposes, propylene oxide was added to the synthesized compounds and for the produced compounds . Surface properties such as surface and interfacial tension, cloud point, wetting time, emulsion stability, and foam height which can be used were measured. They indicate a possibility to use these compounds in the manufacture of textiles, dyes, and cosmetics. Their biodegradability has been evaluated to ensure that these compounds are ecofriendly ones.