3-Hydroxy-4-methyl-2(3H)-thiazolethione (HMTT) is a cyclic thiohydroxamic acid. It forms divalent complexes with the first-row d-block elements Co-Zn. Hydrated form of HMTT exhibits enhanced thermal stability and solubility compared with the anhydrous form. HMTT possess a chelating unit similar to pyrithione. Solid state chemistry of HMTT and its complexes with d-block elements has been reported.