Coumarin derivatives belong to the class of heterocyclic compounds with a benzo-α-pyrone (i.e. coumarin) nucleus. Due to the multitude of coumarin derivatives, the classification, biosynthesis, synthesis in the laboratory and various biological activities such as: antitumor, antiviral, anti-inflammatory, anticoagulant and antioxidant activities are briefly described. Furthermore, coordination modes of a triazole ring are described. The experimental part describes the preparation of 6 complex compounds with the coumarin triazole derivate as a ligand and transition metal nitrates (Zn, Cu, Ag, Co, Hg and Cd). The ligand itself and the prepared complex compounds were characterized by FT-IR spectroscopy and the ligand structure was determined by X-ray diffraction analysis. By comparing the results of the IR spectra of the ligand and the prepared complex compounds, we assume that the binding of ligand and metal cation occurs via thion-triazole ring. In some compounds, in addition to the above mentioned binding, the bond is also established via nitrogen atoms of the triazole group. The results of the research indicate a real possibility for the formation of complex compounds prepared by combining solutions of transition metal salts and prepared triazole coumarin derivate. The methodical part of the paper contains preparation for the teaching unit entitled: Chemical properties of arenes.