Simultaneous SHG (second harmonic generation) and XRD (x-ray diffraction) capabilities have been developed at SSRL (Stanford Synchrotron Radiation laboratory) to examine the phase behavior of energetic materials, for example, HMX (octahydro- 1,3,5,7-tetranitro- 1,3,5,7-tetrmcine) and TATB (1,3,5-triamino-2,4,6 trinitrobenzene). This unique capability provides information on the evolution at the molecular level (centro and non-centrosymmetric) on material stability, phase transformation or decomposition reactions, which are important to continue refinement of computational predictions of material properties. This paper reports x-ray diffraction experiments on both HMX and TATB with increasing temperature and on simultaneous SHG and XRD experiments at fixed temperature. Our results indicate that, for HMX, the {beta} to {delta} transformation occurs over a range of temperature which do not correlate to the previously reported fast rise in SHG signal close to 17OOC as a phase transformation. No phase transition is observed for TATB, even though, previous paper shows an increase in the SHG signal.