On the basis of an asymmetric, conjugated, partially or wholly deprotonated 5-(pyridin-3-yl)-1H-pyrazole-3-carboxylic acid (H 2 ppc),, and [Co(Hppc) 2 (mbbbm)] 2 (5) [mbbbm = 1,3-bis(benzimidazole-1-ylmethyl)benzene)] have been synthesized and characterized magnetically and structurally. Polymer 1, which has the Schlafi symbol (4 2 •6 2 •8 2 ) 2 (4 2 •6•8 3 ) 2 , is a three-dimensional (3D) network. Polymer 2 includes a mononuclear subunit and an infinite two-dimensional (2D) framework subunit, while polymer 3 is a 2D sheet structure. Polymer 4 is characterized by a one-dimensional double ladder-like chain structure. Complex 5 possesses a binuclear structure. Magnetization data for 1 with the Co 2 units show the antiferromagnetic coupling in the Co 2 units. No long-range magnetic ordering is observed for 1. 2, 3, and 5 display weak antiferromagnetic exchange interactions. For 4 with the similar Co 2 units, it also exhibits antiferromagnetic coupling in the Co 2 units, and the M(H) curve is consistent with the antiferromagnetic nature in the Co 2 units. Variable temperature magnetic studies reveal that 2, 3, and 5 display weak antiferromagnetic interactions. The observed magnetization values, which were ∼2.5 Nβ at high field for 2, 3, and 5, are in accordance with the value anticipated for single uncompensated S = 1/2 spin.