The ternary lanthanide Ho(III) complex, [Ho(2,5-DClBA)3(5,5′-DM-2,2′-bipy)]2 (2,5-DClBA=2,5-dichlorobenzoate; 5,5′-DM-2,2′-bipy=5,5′-dimethyl-2,2′-bipyridine) has been successfully synthesized via conventional solution method at room temperature. The complex is characterized by coordination titration analysis, elemental analysis, Infrared spectroscopy and powder X-ray diffraction. In addition, the structure of the complex was characterized by single crystal X-ray diffraction. The results reveal that complex is a binuclear molecular, crystallizing in the triclinic system P ī space group. Each binuclear unit contains two crystallographically independent Ho(III), six 2,5-DClBA and two 5,5′-DM-2,2′-bipy ligands. The binuclear units are assembled into 1D and 2D supramolecular structures by C–H···Cl hydrogen bond and Cl-π interactions. Thermal behavior of the complex was determined by TG-DSC/FTIR techniques. The second thermal decomposition step for complex was calculated by integral iso-conversional nonlinear (NL-INT) method. The value of activation energy E varies slightly with α , indicating that the second decomposition stage of the title complex is single step reaction. Therefore, the improved double equal-double steps method is used to determine the mechanism function of the second thermal decomposition step of the complex. At the same time, the thermodynamic parameters (Δ H ≠ , Δ G ≠ and Δ S ≠ ) and kinetic parameters (activation energy E and the pre-exponential factor A ) of the complex were also calculated. Heat capacity of the complex was measured by a DSC instrument.The experimental molar heat capacity can be fitted to the polynomial equation with the reduced temperature by the means of least square method. Based on the fitted polynomial and thermodynamic equations, the smoothed heat capacity, enthalpy and entropy were calculated.