High-pressure research, whether static or dynamic, provides “windows” to novel states, transformations, and properties of highly compressed extended states of light elemental solids that may comprise the internal structures of giant planets and stars. These low-Z extended solids are extremely hard, have high energy density, and exhibit novel electronic and nonlinear optical properties—superior to other known materials at ambient conditions. These materials are often formed at formidably high pressures and are highly metastable at ambient conditions; only a few systems have been recovered at ambient conditions, limiting the materials to the realm of fundamental scientific discovery. An exciting new research area has recently emerged that aims to understand and ultimately allow for control of the stability, bonding, structure, and properties of low-Z extended solids. This article presents an overview of the basic principles that govern and control the pressure-induced chemistry in dense solids. This is aimed at identifying high energy density, low-Z extended solids that are amenable to up-scaled synthesis and stabilization at ambient conditions.