Architectonic and Desolvation Activation Energies of Five New Mixed-Ligand Copper(II) Coordination Polymers of 5-Sulfoisophthalate and 1,3-Bis(1H-imidazol-1-yl)propane or 1,4-Bis(1H-imidazol-1-yl)butane

Five new coordination polymers, [Cu3(imp)4(sip)2]•2H2O (1), {[Cu3(imp)6(H2O)2.5](sip)2}•15H2O (2), [Cu2(imp)(sip)(OH)(CH3OH)]•CH3OH (3), {[Cu3(timp)6(H2O)4](sip)2}•15H2O (4), and [Cu3 (timp)3(sip)2(H2O)2]•4H2O (5) were synthesized via solvothermal reactions using copper(II) and mixed ligands, including 5-sulfoisophthalate ions, (sip) 1,3-bis(1H-imidazol-1-yl)propane (imp), and 1,4-bis(1H-imidazol-1-yl)butane (timp). Characterization techniques, including FT-IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction, confirmed the successful formation of these polymers. Single-crystal X-ray diffraction revealed that compounds 1, 4, and 5 crystallize in space group P1¯, while 2 and 3 crystallize in P21/c and Pnnm, respectively. All of the coordination polymers include multiple copper ions with different coordination geometries. In compounds 1, 2, 3, and 4, the copper(II) ions have octahedral and trigonal bipyramidal geometries, whereas 5 contains copper(II) ions with square pyramidal and square planar geometries. The thermal behavior of all compounds was investigated under a nitrogen atmosphere. Decomposition occurs within the 150–300 °C range, beginning with desolvation. The activation energies for this process were measured, ranging from 32 to 89 kJ mol–1, providing valuable insights into the compounds’ thermal properties. Notably, desolvation studies indicated similar thermal properties for 1, 3, and 5, which exhibit single-step desolvation, while 2 and 4 dehydrate in two distinct steps.