The tetradentate ligand, 6, 6′-bis (N-methylhydrazine)-2, 2′-bipyridine (L) and its mononuclear copper (II) complex [Cu (L)](ClO4) 2](1) have been synthesized and characterized. The crystal structures of L and 1 have been determined by single-crystal X- ray diffraction. Both crystallize in the centrosymmetric monoclinic space group with crystallographic inversion symmetry. The ligand adopts a planar transoid configuration in ...