Under the condition of solvothermal synthesis, the viologen ligand 1, 1′‐bis(3‐carboxyphenyl)‐(4, 4′‐bipyri‐ dine) dichloride (H₂bcbpy·2Cl) and KI are coordinated with the metal cadmium ions. A case of thermochromic coor‐ dination polymer [Cd(bcbpy)I₂] ·2H₂O (1) was constructed. Complex 1 displays a 1D chain structure and exhibits thermochromic behavior. Under different temperature stimulation, the complex (ground) slowly changed from green to yellow‐green, and with the increase of temperature, the color of complex 1 gradually deepened, and finally became orange‐yellow. Therefore, complex 1 was prepared as a thermochromic film. In addition, we also performed electrochemical tests on complex 1, which showed that the complex is a semiconductor material.

A cobalt-based metal-organic framework [Co₃(L)₂(1, 4-bib)₄]·4H₂O (Co-MOF) was prepared using 5-[(4-carboxyphenoxy)methyl]isophthalic acid (H₃L) and 1, 4-bis(1H-imidazol-1-yl)benzene (1, 4-bib) as ligands. Then, an electrochemical sensor modified with Co-MOF on a glassy carbon electrode (Co-MOF@GCE) was constructed for detecting Cd²⁺ and Pb²⁺ in aqueous solutions. The sensor exhibited a linear range of 1.0-16.0 μmol·L^-1 with a detection limit (LOD) of 4.609 nmol·L^-1 for Cd²⁺, and 0.5-10.0 μmol·L^-1 with an LOD of 1.307 nmol·L^-1 for Pb²⁺. Simultaneous detection of both ions within 0.5-7.0 μmol·L^-1 achieved LOD values of 0.47 nmol·L^-1 (Cd²⁺) and 0.008 nmol·L^-1 (Pb²⁺), respectively. Analysis of real water samples (tap water, mineral water, and river water) yielded recoveries of 95%-105%, validating practical applicability. Density functional theory (DFT) calculations reveal that synergistic interactions between cobalt centers and N/O atoms enhance adsorption and electron-transfer efficiency. CCDC: 2160744.