In vitro analysis indicates that some thiosemicarbazones show potential as chemotherapeutic agents and Triapine (3-aminopyridine-2- carboxaldehyde thiosemicarbazone) showed promising results passing several phase I and II clinical trials. The study of relationship between chemical structure of thiosemicarbazones and their antiproliferative activity presented that the minimum requirement for biological activity is a pyridine cycle with nitrogen in α-position to the thiosemicarbazide side chain. Also, there was observed that dialkylation of the terminal nitrogen (N4 ) can increase the overall cytotoxicity and also influence the lipophilicity of thiosemicarbazones. Taking into consideration the abovementioned, three new proligands, Triapine analogues, were obtained through Schiff base condensation. In addition, three Copper (II) complexes were synthesised by direct complex formation reactions of proligands with CuCl2·2H2O in molar ratio 1:1, performed in Schlenk tubes under argon for avoiding oxidation of the 4-hydroxy-3,5- dimethylphenyl moiety, which have redox proprieties. The chemical structures of all synthesised compounds were in agreement with the expected structures. The NMR spectra confirmed the purity of the compounds, while all 1H, 13C, 15N signals could be assigned respectively. The ESI mass spectra recorded in positive and negative ion mode showed mass peaks with corresponding isotopic distribution. The purity of the compounds was confirmed by elemental analysis. The stability study of all compounds by cyclic UV-Vis analyse showed their stability in time. Cyclic voltammetry experiments of complexes showed that in addition to the metal-centred Cu(II)/(I) redox couple several ligand-centred oxidations take place, which are characteristic for dimethyl moiety. This oxidation peaks were also observed in cyclovoltammograms of ligands. The exact structure was described by X-ray diffraction study on monocrystalls. The influence of Cu(II) on the antiproliferative activity of the metal-free ligands was studied by comparison of the cytotoxic activity of proligands and their metal complexes in two cancer cell lines – doxorubicin-sensitive Colo-205 (colon cancer) and multidrug resistant Colo-320 colonic adenocarcinoma cells (MDR colon cancer) as well as in normal non-cancer lung cell lines MRC-5.