The syntheses and properties of the Ni(II) and Co(II) complexes, [M(H 2ETC)], of the macrocyclic ligand, 2,3-ethylene-5,5:13,14-di(5′-methylbzo)-9,10-4′,5′-diolbzo)-[14]-1,4,8,11-[N 4]-7,12-diene, [H 4ETC] are reported. The ligand contains a central tetraaza cavity and ✓ a peripheral catecholate function fused to the tetraaza macrocycle. The appended catechol function allows the [M(H 2ETC)] complexes to serve as substituted catecholate ligands for other metal ions. This is demonstrated in the synthesis of the [NiETC] 2Cu 2− complex which has been structurally characterized. The [M(H 2ETC)] complexes (M = Ni, Co) can be crystallized in two forms: either as monomeric species with two solvent molecules hydrogen-bonded to the catechol hydroxyl groups or as dimeric species with the catechol hydroxyl groups hydrogen-bonded to each other and a single solvent molecule. The complex {[Ni(H 2ETC)]·2THF}, { IV·2THF}, crystallizes in the triclinic space group P 1 with a = 10.908(1), b = 11.391(3), c = 12.727(2), α = 84.56(2), β = 80.28(2) and γ = 73.39(2). The complex [Co(H 2ETC)]·THF2, {( VI)·THF} 2, crystallizes in the triclinic space group P 1 with a = 11.134(4), b = 13.383(6), c = 17.286(6), α = 77.42(3), β = 76.18(3) and γ = 88.41(3). The complex {[Co(H 2ETC)]·DMF} 2 {( VI)·DMF} 2 crystallizes in the monoclinic space group P1 1/ n with a = 9.087(2), b = 7.962(2), c = 34.012(7) and γ = 94.55(2). The {[NiETC] 2Cu} 2− complex, ( VII)·4DMF crystallizes in the monoclinic space group P2 1/ c with a = 10.26(2), b = 35.21(4), c = 12.541(13) and γ = 95.54(11). Single crystal X-ray diffraction data for all crystals were collected on an automated diffractometer using MoKα radiation and the structures solved using conventional methods. Full-matrix refinement of 378 parameters on 3749 data for VI·2THF, 308 parameters on 2030 data for {( VI)·DMF} 2, 341 parameters on 4244 data for {( VI)·THF} 2, and 290 parameters on 399 {( VII)·4DMF} gave final R values 0.062, 0.066, 0.050, and 0.062, respectively. The metal coordination geometry in the low spin ( S = 1 2 ) [CoH 2ETC] complex and the diamagnetic [NiH 2ETC] complex is square planar and the MN bonds are 1.865(5) Å and 1.860(5) Å, respectively. The {[NiETC] 2Cu} 2− complex is a monomeric species and contains two NiN 4 and one CuO 4 planar chromophores. The paramagnetic CuO 4 chromophore ( S = 1 2 ) is not subject to intermolecular bonding interactions and shows a CuO bond of 1.917(6) Å. The intramolecular NiCu and NiNi distances in the centrosymmetric molecule are 7.676(2) Å and 15.352(2) Å, respectively.