Chemists can rationally regulate the reactivity of molecules and functional groups in both industrial and laboratory-based synthetic organic chemistry processes. The concept can be applied to inorganic nanomaterials including two-dimensional (2-D) black phosphorus (BP) nanosheets. For example, scientists can "shut down" the high reactivity of few layer or monolayer black phosphorus, when the compound is not in use, to resume its activity upon application. In a new report now published on Science Advances, Xiao Liu and a team of scientists in physics, biomaterials, chemical engineering and biological chemistry in China developed a protective chemistry-based method to regulate the reactivity of black phosphorus.