Two coordination modes around the Cu(II) cations in complexes with benzo[b]furancarboxylic acids

► Cu(II) complexes with three benzo[b]furancarboxylic acids are structurally investigated. ► Metal-ligand interactions are studied by X-ray absorption spectroscopy. ► Depending on the ligand, mononuclear and dinuclear Cu(II) complexes have been obtained. ► X-ray crystal structure analysis of dinuclear complex has been performed. ► For one of the complexes different coordination modes exist in crystal and powder form.