New biscarboxylato zwitterionic ligands, namely bis(N-carboxylatoethyl)-4,4-dipyridinum) L 1 and bis(Ncarboxylatopropyl)-)-4,4-dipyridinum) L 2 , were synthesized from the reaction of 4,4-dipyridine with 3-bromopropanoic acid and 4-bromobutanoic acid, respectively. The reaction of these ligands and the azido coligand with some metal ions resulted in the formation of polymeric complexes of general formulae [Cr 2 (L n)(N 3) 4 ]Cl 2 •H 2 O and [M 2 (L n)(N 3) 4 ] xH 2 O, where (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); n = 1, 2; x = 1, 1, 1, 1, 0, 1, and 1, respectively.) The oxygens of the carboxylato group are coordinated to the metal ion in a bidentate fashion. The mode of bonding and overall geometry of the complexes were determined through IR, UV-VIS, NMR and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, chloride content and conductance. These studies revealed the formation of polymeric assemblies of six-coordinate complexes with distorted octahedral geometries about metal centers.