Ab initio total energy calculations with the DFT framework based on the geometries obtained by X-ray data were carried out for five complexes composed by copper(II) ion and organic radicals (eg. aminoxyl and carbene) through pyridine, bipyridine and terpyridine rings. It was found that the copper(II) complex having radical substituted at 4-position of aromatic ligand favors ferromagnetic coupling between organic radical and paramagnetic copper(II) ion.