We performed theoretical studies to predict the molecular structure. molecular properties, and explosive performance of 4,4',5,5'-tetranitro-2,2'-bi-1H-imidazole (TNBI). High levels of ab initio and density functional theories were employed to predict the molecular structure of TNBI. Predicted TNBI structure was in good agreement with that observed by X-ray crystallography. Heat of formation in the solid phase at 298 K was predicted to be 270.3 kJ/mol. Density of TNBI was predicted to be 1.919-1.956 g/cm(3) depending upon the parameter sets of group additivity method. By using these values as input data, we estimated detonation velocity and C-J pressure to be 8.69-8.80 km/s and 34.5-36.1 GPa, respectively. Impact sensitivity of TNBI was predicted to be 33 cm.