The low-temperature molar heat capacity of crystalline Ni9(btz)12(DMA)6(NO3)6 (1) (btz = benzotriazolate; DMA = N,N′-dimethylacetamide) was measured by temperature-modulated differential scanning calorimetry for the first time. The thermodynamic parameters such as entropy and enthalpy relative to reference temperature 298.15 K were obtained based on the above molar heat capacity data. The compound was synthesized by solvothermal method and characterized by powder X-ray diffraction and FT-IR spectra. Moreover, the thermal stability and the decomposition mechanism of Ni9(btz)12(DMA)6(NO3)6 were investigated by thermogravimetry (TG) analysis under air atmosphere from 300 to 873 K. The experimental results through TG measurement demonstrate that the compound has a two-stage mass loss in air flow.