Two new coordination polymers [Co3(pta)2(bztpy)(H2O)2]·2H2O (1) and [Co3(bta)2(bztpy)1.5(H2O)2]·4H2O (2) (H3pta = 1,2,3-propanetricarboxylic acid, H3bta = 1,2,3-benzenetricarboxylic acid, bztpy = 1,2,4,5-tetra(4-pyridyl)benzene) have been hydrothermally synthesized and structurally characterized. In 1, pta connects with a trinuclear cobalt cluster to form a (4,4) net, while bztpy also connects with the trinuclear cobalt cluster to form a (4,4) net, thereby creating a very rare (4,8)-connected mixed-node topological network that exhibits ferrimagnetic behavior. 2 is a rare (4,4,12)-connected topological network formed by hexanuclear cobalt rings connected through 12 bztpy ligands, showing antiferromagnetic properties. Both compounds demonstrate the potential of the large tetradentate pyridyl ligand bztpy in constructing high-connectivity topological networks.