Interaction of Pd(II), Pt(II), Ag(I), and Au(III) with 4,6-diamino-2-thiopyrimidine (DATP) and 4,6-diamino-2-methyl-thiopyrimidine (DAMTP) in aqueous medium resulted in the formation of new complexes which have been characterized by elemental analysis, ir,1H-nmr spectroscopic techniques, magnetic susceptibility measurements in the solid state, and conductivity measurements in DMF solution. The ir and1H-nmr spectra were consistent with coordination involving the non-protonated ring nitrogen atom, the exocyclic sulphur atom, orN,S-chelation.