A well-documented body of both experimental and theoretical studies seems to suggest systematic phase/chemical transformations of low Z molecular solids to covalent solids, ionic solids and, eventually, metallic solids under extreme conditions. Inspired by this emerging theme, we have performed an integrated research program of small-scale static and large-scale dynamic high pressure-temperature experiments using synchrotron X-rays, X-ray Free Electron Laser (XFEL) and the National Ignition Facility (NIF), to investigate the evolution of chemical bonding, crystal structure and properties of low Z solids under extreme conditions. In this talk, I will first briefly describe several fundamental principles governing the chemistry of low Z solids under extreme conditions and, then, present our recent results of (i) NIF-Discovery Science Campaign on ramp-compressed NaClto 1TPa, (ii) MHz time-resolved X-ray diffraction (TR-XRD) at Eu-XFEL to probe the structure evolution of N2 under rapid compression in dynamic-DAC, and (iii) KHz TR-XRD at APS to probe the formation of superionic ice phases under rapid heating in ramp laser-heated DAC.