4-benzoylpyridine thiosemicarbazone (H(4)Bz(4)DH) and N(4')-phenyl-4-benzoylpyridine thiosemicarbazone (H4Bz4Ph) were obtained and fully characterized by infrared, UV and NMR spectroscopies. The assignment of the NMR signals was made by using DEPT135 and the HMQC heteronuclear correlation technique. X-ray diffraction studies have shown the presence of a water molecule in the crystal structure of both compounds as well as the protonation of the pyridine nitrogen. Moreover, a Cl- counter-ion was evidenced in the crystal structure of H4Bz4DH and an HSO4- ion in the structure of H4Bz4Ph. Refined structures of both compounds are included and the X-ray crystallographic studies can be summarized as follows: H4Bz4DH(+)Cl(-).H2O crystallizes with triclinic symmetry, space group P1, with a = 9.159(2), b = 9.749(2) and C = 17.787(4) Angstrom, alpha = 81.75(3), beta = 81.24(3) and gamma = 69.41(3)degrees and Z = 4. H4Bz4Ph(+)HSO(4)(-).H2O crystals have monoclinic symmetry, space group C2/c, with a = 32.767(7), b = 10.149(2) and c = 12.763(3) Angstrom, beta = 99.23(3)degrees and Z = 8. (C) 2002 Elsevier Science B.V. All rights reserved.