A new complex, [Cd(succ)PIP]n (PIP=2-phenyl-imidazo[4,5-f]1,10-phenanthroline, H2-succ=succinate), was synthesized and characterized by X-ray crystallography, elemental analysis, and TG-DTG. The results show that the complex crystallizes in an orthorhombic space group Pcca; a=14.065(2) angstrom, b=9.901(8) angstrom, c=28.933(2) angstrom and Z=8. The structure of the complex is one-dimensional chain [Cd(succ)PIP]n, and each Cd2+ is five-coordinated by two chelating nitrogen atoms from one PIP ligand, three oxygen atoms from three different succ dianionic ligands to form a distorted trigonal-bipyramida geometry. The constant-volume combustion energy of the complex, ?cU, was determined by an intelligent micro-rotating-bomb calorimeter (IMRBC-type I) at 298.15 K. Then the standard molar enthalpy of combustion, ?cHm?, and the standard molar enthalpy of formation, ?fHm? have been calculated.