4, 5-diaryl-5, 1-dihydro-s-trazol-3-thiols have been synthesized via cyclization of 1-arylaminomethylthio-semi-carbazide derivatives using concentrated hydrochloric acid or from the reaction of arylaminomethydrazine derivatives with carbon disulphide in alkaline medium. Some heterocyclic system viz, pyrazolidinyltriazoline, thiazolidinyl-aminotriazoline, triazinotriazolidine and tetrazinyltriazoline, have been derived from 3-hydrazinotriazoline derivative, obtained from reaction of the title compound with hydrazine. The structures of the new compounds have been established by elemental analyses and spectral data.