Two new Cd(II) complexes, {[Cd(COO)2]2·2H2O} n (1) and {[CdCl(COO)2(Hbmi)]·H2O} n (2), were obtained through the reactions of oxalic acid (H2ox) with CdCl2 ·2.5H2O in the presence of 1‐[(benzoimidazol‐yl)methyl]‐1H‐tetrazole (bmt) or 1‐[(benzoimidazol‐yl)methyl]‐1H‐imidazol (bmi). Single‐crystal X‐ray diffraction shows that complex 1 has a 3‐D structure with the topological notation of (48 · 62)(46 · 66 · 83)(42 · 84), in which the oxalate displays two kinds of coordination modes: formation of the layers (μ6‐ox) and linking the layers (μ4‐ox). In complex 2, oxalates bridge Cd(II) ions, forming a 1‐D chain, and (Hbmi)+ cations coordinate to the Cd(II) ions in monodentate mode and hang at two sides of the main chain. This indicates that subtle modification of the N‐donor ligands can result in complexes with different compositions and architectures. Moreover, their IR spectra, PXRD (powder X‐ray diffraction) patterns, thermogravimetric analyses, and fluorescence properties are also investigated.