Abstract: The chemistry of life is based considerably on chirality. Consequently, stereospecificity has to be regarded as an especially important characteristic of biological systems. The influence of stereospecificity of the biological activities of enzyme inhibitors or compounds binding to receptor is a well known fact in the field of drug action^[1]. s-Triazoles and l,3,4-thiadiazoles are reported to exhibit broad spectrum of biological and pesticidal activities^[2-3].In recent years, bridge head nitrogen heterocycles have received much attention as anthelmintic agents, however, it is not observed that the syntheses of chiral fused heterocyclic compounds containing s-triazoles and l,3,4-thiadiazoles. In order to study the relationship between stereochemistry and the performance of fungicides, we have synthesized a series of (s)-1,2-di(3-aryl-s-triazolo[3,4-b][1,3,4] thiadiazolo-6-yl) ethylamine and (s)-1-(3-aryl-s-triazolo[3,4-b][l,3,4] thiadiazolo-6-yl) ethylamine by the condensation of 3-aryl-4-amino-5-mercapto-1,2,4-triazoles with L-aspartic acid and L-alanine in the presence of phosphorusoxychloride.