Two macrocyclic nickel(II) complexes, [Ni(L)(a,e-cis-1,4-chdc)]4H(2)O (1) and [{Ni(L)(H2O)}(2)(e,e-trans-1,4-chdc)](ClO4)(2) (2) (L = 1,4,8,11-tetraazacyclotetradecane, cyclam), were prepared by the reaction of [Ni(L)](ClO4)(2) and a,e-cis-/e,e-trans-1,4-chdcH(2) in basic solvents. Both complexes were characterized by EA, IR, and TGA techniques. In addition, molecular structures were determined by single crystal X-ray diffraction methods. In 1, the a,e-cis-1,4-chdc ligand bridges nickel(II) macrocycles to form an undulated 1D coordination polymer, whereas the complex 2 shows a dimer in which the e,e-trans-1,4-chdc ligand bridges two nickel(II) cyclams.