Synthesis and crystal structures of the first cobalt complexes of macrocyclic oxamido

► A novel macrocyclic oxamido-cobalt (II) complex CoL was synthesized. ► Based on the complex ligand CoL, three polynuclear complexes were prepared. ► These macrocyclic oxamido-cobalt complexes were characterized structurally first. ► It affords a new ligand to synthesize polynuclear or high-dimensional complexes.