This article presents a method for producing high-quality, few-layer black phosphorus (BP) nanosheets in large quantities using liquid phase exfoliation under ambient conditions. The nanosheets are stable in N-cyclohexyl-2-pyrrolidone (CHP) due to the solvation shell protecting them from reacting with water or oxygen. Experiments and simulations show that reactions occur only at the nanosheet edges, with the rate and extent depending on the water/oxygen content. The liquid-exfoliated BP nanosheets exhibit photoluminescence and can be size-selected by centrifugation. They show nonlinear optical properties, making them suitable for optical switching applications, and can also be used as gas sensors and fillers for composite reinforcement. The study demonstrates the potential of liquid exfoliation for producing BP nanosheets with applications beyond electronics, such as gas sensing and composite reinforcement.This article presents a method for producing high-quality, few-layer black phosphorus (BP) nanosheets in large quantities using liquid phase exfoliation under ambient conditions. The nanosheets are stable in N-cyclohexyl-2-pyrrolidone (CHP) due to the solvation shell protecting them from reacting with water or oxygen. Experiments and simulations show that reactions occur only at the nanosheet edges, with the rate and extent depending on the water/oxygen content. The liquid-exfoliated BP nanosheets exhibit photoluminescence and can be size-selected by centrifugation. They show nonlinear optical properties, making them suitable for optical switching applications, and can also be used as gas sensors and fillers for composite reinforcement. The study demonstrates the potential of liquid exfoliation for producing BP nanosheets with applications beyond electronics, such as gas sensing and composite reinforcement.