Mixed-ligand complex compounds of diclofenac with Zn+2 metal cation and ethylene diamine were synthesized, its molecular crystal structure was determined by X-ray diffraction analysis (XRD), IR spectroscopy, and stability by TG-DSC. Based on the RSA results, it was established that the general formula of the zinc complex compound consists of [Zn(EDA)2(H2O)2](Dicl)2(H2O)2. Studies of the antibacterial activity of the newly obtained complex compound were conducted under in vitro conditions on strains of gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, gramnegative bacteria Escherichia coli and the fungus Candida albicans. As a result of the conducted research, it was proven that the antibacterial activity of the newly obtained complex compound is significantly higher compared to diclofenac, and also, the high biological effectiveness of mixed-ligand complex compounds compared to monoligand metal complexes has been proven.