Three isomorphous coordination polymers based on the chain with triple (mu-1,1-N-3)(mu-1,3-COO)(2) bridges have been synthesized from a new zwitterionic dicarboxylate ligand [L- = 1-(4-carboxylatobenzyl)pyridinium-4-carboxylate]. They are of formula [M(L)(N-3)](n)center dot 3nH(2)O [M = Mn-II, Co-II, and Ni-II]. In these compounds, the mixed-bridge chains are linked into 2D coordination networks by the N-benzylpyridinium spacers. The magnetic properties depend strongly on the nature of the metal center. The magnetic coupling through (mu-1,1-N-3)(mu-1,3-COO)(2) is antiferromagnetic in the Mn-II compound but ferromagnetic in the Co-II and Ni-II analogues. Magnetostructural analyses indicate that the magnitude of the magnetic coupling can be correlated to the M-N-M angle of the azide bridge and the average M-O-C-O torsion angle of the carboxylate bridge. As the values of these parameters increase, the antiferromagnetic coupling for Mn-II decreases while the ferromagnetic coupling for Co-II increases. With strong magnetic anisotropy, the Co-II compound behaves as a single-chain magnet showing hysteresis and Glauber-type slow dynamics probably in the infinite-chain region, with Delta(tau)/k = 86 K, Delta(xi)/k = 26 K, and Delta(A)/k = 34 K. With weaker anisotropy, the Ni-II species shows slow relaxation of magnetization at much lower temperature.