The synthesis of a terpyridine-guanosine ligand and its reaction with copper(II) to yield a new [2 + 2] metallo-rectangle is reported. The metallo-rectangle was characterized by single crystal X-ray diffraction and the structure showed significant intramolecular π-π stacking interactions between the two terpyridine moieties of the molecule. This prompted us to investigate the magnetic properties of the new di-copper(II) assembly which displayed ferromagnetic interactions in the solid state.