This paper presents the results on the synthesis and study of the structure of a new mononuclear complex of copper nitrate with 2-amino-5-ethylthio-1,3,4-thiadiazole and 1,10-phenanthroline. Using the method X-ray diffraction analysis, the structure of the complex was studied. It was shown that copper (II) nitrate forms a five-coordinated complex with a distorted tetragonal pyramidal structure with 2-amino-5-ethylthio-1,3,4-thiadiazole and 1,10-phenanthroline molecules, in the inner sphere of which three thiadiazole ligands and an 1,10-phenanthroline molecules are coordinated to the complexing agent; thiadiazole ligands are bonded as a monodentate through endocyclic nitrogen, the 1,10-phenanthroline is bonded as a bidentate, the nitrate anions are located in the outer sphere forming a cationic complex.