The reaction of heterocyclic thiolic derivatives HLnwith dimethylthallium(III) hydroxide yields Me2TlL compounds. The structure of dimethyl(1-oxidopyridinium-2-thiolato)thallium(III), Me2TlL5T, has been determined by X-ray analysis. Me2TlL5 crystals are monoclinic, space group P21/c, with a = 9.812 (3) Å, b = 7.616 (1) Å, c = 12.851 (3) Å, β = 97.48 (3) °, and Z = 4. The structure was refined to R = 0.016 for 929 unique data. In this compound the thallium atom is six-coordinate, if weak bridging interactions are considered, in lattices with polymeric chains. Spectroscopic data for the complexes OH, 13C, and 205T1 NMR, IR, and Raman) are discussed in order to determine possible structural/spectroscopic correlations. © 1988, American Chemical Society. All rights reserved.