The octahedral nickel(II) complexes, [[Ni(L)(tp)]center dot 2H(2)O (1) and [[Ni(L)(isoph)(2)]center dot 2H(2)O (2) (L = 1,3,10,12,16,19-hexaazatetracyclo[17,3,1,1(12.16),0(4.9)] tetracosane, tp(2-) = terephthalate, isoph(2-) = isophthalate) were obtained by the reaction of [Ni(L)](ClO4)(2)center dot 2H(2)Owith corresponding ligands. These complexes have been characterized by X-ray crystallography, spectroscopic and magnetic susceptibility. The crystal structure of 1 shows a distorted octahedral coordination geometry with two secondary and two tertiary amines of the macrocycle and two oxygen atoms of the tp 2-ligand, which reveals a 1D coordination polymer. Electronic spectra of the complexes in solid state exhibit a high-spin octahedral environment. The magnetic behavior of 1 reveals a very weak antiferromagnetic interaction with J values of -1.19(3) cm(-1).