A new energetic copper complex of dinitroacetonitrile (DNANT), [Cu(NH3)(4)](DNANT)(2), was first synthesized through an unexpected reaction. The thermal decomposition of [Cu(NH3)(4)](DNANT)(2) was studied with DSC and TG/DTG methods. The gas products were analyzed through a TG-FTIR-MS method. The nonisothermal kinetic equation of the exothermic process is d alpha/dT = 10(10.92)/beta 4(1-alpha)[-ln(1 - alpha)](3/4) exp(-1.298 x 10(5)/RT). The self-accelerating decomposition temperature and critical temperature of thermal explosion are 217.9 and 221.0 degrees C. The specific heat capacity of [Cu(NH3)(4)](DNANT)(2) was determined with a micro-DSC method, and the molar heat capacity is 512.6 J mol(-1) K-1 at 25 degrees C. Adiabatic time-to-explosion of Cu(NH3)(4)(DNANT)(2) was also calculated to be about 137 s.