The complexes of Cu(II) were synthesized with the new macrocyclic ligand. The newly synthesized azamacrocyclic ligand L: 5,15-dibromo-9,10,11,20,21,22-hexamethyl-1,8,12,19-tetraazadicosa- 9,11,20,22- tetraene was prepared by the reaction of 3-Methyl-2,4 pentadione and 5-bromo-2,6-diamino pyridine. All the complexes were characterized by the conductance measurements, magnetic susceptibility measurements, mass, I.R. electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMF solution is corresponding to non-electrolyteic nature. Thus these complexes may be formulated (M(L)X2) (where M = Cu (II) and X = Cl - , CH3COO - and NO - 3).On the basis of spectral studies, tetragonal geometry was assigned for for Cu(II) complexes. Complex was then used as a good sensing material for oxalate ion selective PVC membrane sensor. The proposed potentiometric sensor showed a stable potential response to oxalate ion with Nernstian slope-29.0 mV decade -1 over a wide linear concentration range of 5.0x10 -7 - 6.0x10 -1 M. The sensor was found to have a short response time of about 10-15 s and have an accepted life time. Application of the proposed sensor in analysis of oxalate ion in some water samples showed good results.