2-Triazolylhydrazines underwent ring closure with aliphatic acids or ortho esters to thiazolo [2, 3-c]-s-triazoles, cyanogen bromide, and carbon disulfide readily giving the corresponding% amino and 3-mercapto derivatives. The isomeric thiazolo [3, 2-b]-s-triazole system was readily obtained from s-triazole-&thiols and a-halo ketones. Spectral characteristics of these ring systems are described.