The pressure/temperature and reaction phase diagram for dinitro azetidinium dinitramide (DNAZ-DN) has been delineated using a high-pressure diamond anvil cell with Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and optical polarizing light microscopy. The phase diagram was determined between ambient pressure and 10.0 GPa over the temperature range from -75 degrees C to decomposition temperatures or > 150 degrees C, The phase diagram delineates the melt curve for alpha-DNAZ-DN, a reversible phase transformation in alpha-DNAZ-DN forming a new high-pressure polymorph, beta-DNAZ-DN, and also identifies the pressure and temperature conditions for solid state decomposition of beta-DNAZ-DN. FTIR and Raman spectra were obtained for both the alpha and beta phases as a function of pressure at room temperature. The new high-pressure beta polymorph could not be retrieved to ambient conditions.