A new 20-dentate macrocyclic hydrazone ligand obtained from 2,6-diacetylpyridine and oxalic dihydrazide was synthesized using template method. A mixture of Co(SCN)2 – 2,6diacetylpyridine – oxalic dihydrazide in 1:1:1 molar ratio was refluxed for about 3 hours to obtain a green precipitate. Crystals suitable for X-ray study of a new Co(II) tetranuclear complex cation with this ligand (Fig. 1) and  4 HSO anion in the external sphere have been obtained via deprotonation-protonation method. In the IR spectrum, 2,6diacetylpyridine fragment is supported by ν(CH3) 2933, 2855 cm-1 and δ(CH3) 1462 and 1385 cm-1; dihydrazide fragment by ν(NH) 3210, and ν(C=O) 1638 cm-1. A broad band at 3350 cm-1 is attributed to associated ν(OH). The  4HSO anions show strong bands at 1038, 1019 and 859 cm-1. The X-ray single crystal study has shown that in the Co(II) tetranuclear complex cation for each seven-coordinated metallic atom with a pentagonal-bipyramidal environment the donor atoms O4N3 are provided by one quarters of twentydentate Schiff base ligand and two water molecules. The distances Co–O(cetonic) 2.202(5), Co–N) 2.193(7) and 2.171(10) Å are similar to those founded in the mononuclear Co(II) complexes with hydrazone Schiff base. The apical coordination positions are occupied by water molecules (Fig. 1) The Co–O(w) distance are 2.08(1) and 2.123(9) Å. The tetranuclear cations in the crystal are arranged in such a way that form tubular channels [total potential solvent area volume is 5358.9 Å3 (61,9 %) without solvent molecules] (Fig. 2). In these channels are found the crystallization water molecules which are weak bonded to macrocycle ligands. The  4HSO anions are bound to tetranuclear complex cations through O(W)–H···O* and N(1)–H···O* hydrogen bonds and the donor···acceptor distances are 2.689(10) and 2.767(9) Å.