AbstractA 1D double‐helical coordination polymer {[Cd(pbbm)2]2(ClO4)4(H2O)2}n (1) was successfully constructed by the reaction of Cd(ClO4)2·6H2O with 1,1′‐(1,5‐pentanediyl)bis‐1H‐benzimidazole (pbbm). Interestingly, polymer 1 exhibits highly selective capacity for the ionic exchange of Zn2+ and Cu2+ over Co2+ and Ni2+ ions in the crystalline solid state when the crystals of 1 are immersed in the aqueous solutions of the perchlorate salts of Cu2+, Zn2+, Co2+, and Ni2+ ions, respectively, which indicates that central CdII ion exchange might be considered as being dominated by the coordination ability of metal ions to free functional groups, ionic radii of exchanged metal ions, and the solution concentration of adsorbed metal salts. The parent material‐ and ion‐exchange‐induced products are identified by FT‐IR spectroscopy, PXRD patterns as well as SEM and EDS measurements. In addition, the thermal stability of 1 was also investigated.