2,4,6,8- Tetranitro - 2,4,6,8- tetraazabicyclo[3.3.1]nonane-3,7-dione (TNPDU) has been synthesized from propane diurea by nitration with nitric acid-acetic anhydride with a yield of 85 %. The molecular structure pf the compound has been determined by elemental analysis, IR and H-1-NMR spectroscopy. Some of the properties including thermal and explosion delay behaviour of the compound and its mixtures with high explosives, are reported. An analogous compound 2,5,7,9-tetranitro-2,5,7,9-tetraazabicyclo[4.3.0]nonane-8-one (TNABN) has also been evaluated for some of the explosive properties considering its good stability and insensitiveness as compared to other nitrodiurea derivatives.