Nonporous hybrid metal–organic materials self-assembled by a ditopic organic ligand and copper(II) have shown a dynamic behavior by releasing and trapping HCl. The solid-state process involves major structural reorganizations comprising cleavage and formation of coordination and covalent chemical bonds by mechanochemical reactions, heating reactions or chemisorption. Single crystal X-ray diffraction, powder X-ray diffraction and TGA in combination with DFT specific for solid-state systems have been used to study the solid-state reactivity.