Five mixed-ligand complexes containing 1,2-ethanediol, water and zinc sulphate were prepared. Two types of mixed-ligand complexes were observed on the basis of the thermal decomposition patterns and water bonding bands. Their thermal stabilities and IR spectra were investigated. The crystal structure of Zn(1,2-ethanediol) 2(H 2O) 2(SO 4) was determined by X-ray diffraction. Both 1,2-ethanediol and water coordinate to the zinc ion. The 1,2-ethanediol molecules are bonded to two zinc ions, forming a polymer network.