Isonicotinic acid hydrazide (isoniazid), known in medical practice as tubazide, is an organic compound that is used in medicine for prophylaxis and treatment of tuberculosis. This substance manifests one of the best bacteriostatic activities against Mycobacterium tuberculosis H37Rv, but it also has high toxicity and, therefore, its use as a medicine is limited. Using isoniazide as initial substance by the reaction of condensation with 2-hydroxy-3-methoxybenzaldehyde it was obtained 2-hydroxy-3-methoxybenzaldehyde isonicotinoylhydrazone (H2L). Monocrystals of H2L were obtained as a result of recrystallization from ethanol and their crystal structure was determined by X-ray analysis. Ligand H2L represents almost planar molecule except methoxy group. Also it was synthesized one coordination compound of Cu(II) with H2L. Its composition and probable structure was determined on the basis of data from elemental analysis and magnetochemistry:formulaThe data obtained from the study of antituberculous properties is shown in the table. This research indicates that the free ligand H2L and coordination compound Cu(HL)Cl manifest bacteriostatic activity at the concentrations 10 and 20 μg/mL. These substances inhbit the growth of tuberculosis bacteria H37Rv for the first two weeks.tableAntituberculous activity of the synthesized substances is comparable with the activity of medicaments used in medical practice.