In the present work, we report the synthesis and characterization of two new heterometallic coordination polymers based on CeIII and containing CoII or CuII cations, assembled by the bifunctional ligand 1H-imidazole-4,5-dicarboxylic acid, [Ce(H2O)2(HIDC)Co(IDC)]·H2O CoCe and [Ce(H2O)2(H2IDC)Cu(H2O)(IDC)Cu0.2(H1.6IDC)] CuCe. Compound CoCe was obtained under one pot hydrothermal synthesis, while CuCe was synthesized by a step-by-step synthesis using the metalloligand [Cu(H2IDC)2(H2O)2] Cu1, as precursor. From a structural point of view, CoCe presents an intrincated 3D structure, in which alternating chiral CoII chains can be observed, which are assembled by discrete CeIII fragments, giving rise to the 3D structure. Meanwhile, CuCe presents a structure formed by [Cu2Ce2] heterometallic chains, partially assembled by CuII cations in a 2D structure. Magnetic properties reveal that both CoCe and CuCe present a global antiferromagnetic behavior, dominated by the interaction between CoII-CoII or CuII-CuII entities connected by μ2-O′′′,N′ bridges, belonging to H3IDC anionic derivatives. Moreover, a weak ferromagnetic phenomenon was found in compound CoCe, corroborated by hysteresis loops and ac magnetization. © 2018 American Chemical Society.