The thiosemicarbazones and their transition metal complexes are relevant for study due to their diverse biological activity. Such compounds have a lot of diverse applications: anticancer, antibacterial, antiviral, antifungal, anti-HIV. Mixed-ligand complexes play an important role in biological systems because the combination of different ligands can result in substances with higher and more promising biological activities. For this purpose, the 4-allylthiosemicarbazone N-(4-methoxyphenyl)-2oxopropanamide HL (Fig. 1) was synthesized by the interaction between 4allylthiosemicarbazide and N-(4-methoxyphenyl)-2-oxopropanamide in ethanol in molar ratio 1:1.Figure 1. The structure of HL The obtained HL was studied by NMR and FTIR spectroscopy. The mixed-ligand complexes were obtained by two step mechanism. At the first step the copper(II) coordination compound Cu(L)NO3 was obtained by reaction between HL and Cu(NO3)2·3H2O in ethanol with heating in molar ratio 1:1. At the second step the corresponding N-heteroaromatic base (1,10-phenantroline, 2,2’-bipyridyl, 3,4-lutidine, 3picoline, 4-picoline, pyridine, imidazole) was added to the ethanolic solution of Cu(L)NO3. The composition of these compounds was determined using elemental analysis for copper: Cu(A)(L)NO3 (A = 1,10-Phen, 2,2’-Bpy, 3,4-Lut, 3-Pic, 4-Pic, Py, Im). A standard ABTS•+ method has been used to determine the antioxidant properties of synthesized compounds. The values of IC50 are in the range 61.32-99.31 μM. The most active one is complex with 3-picoline into the inner sphere.