Compared with the intriguing five–ligand coordination compound of [Cu(IMI)4Cl]Cl (IMI = Imidazole, 2), multi–ligand coordination compound of Cu(Trz)4Cl2 (1) was synthesized by using 1,2,4-Triazole (Trz) and characterized by elemental analysis and FT–IR spectrum. The crystal structure was determined by X–ray single crystal diffraction and the crystallographic data showed that the crystal belongs to tetragonal, pertains to I41/acd space group, α = 14.4013(4) Å, b = 14.4013(4) Å and c = 15.7049(10) Å. Furthermore, the copper(II) cation of 1 is six-coordinated with four atoms from four Trz molecules and two Cl atoms, however, the Cu(II) ion of 2 is infrequent five–coordinated with four N atoms from four IMI ligands and a chlorine atom. Thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC), and the non–isothermal kinetics parameters were calculated by the Kissinger’s method, Ozawa’s method and Starink’s method, respectively. The energy of combustion, enthalpy of formation, critical temperature of thermal explosion, entropy of activation (ΔS≠), enthalpy of activation (ΔH≠), and free energy of activation (ΔG≠) were also measured and calculated.