Abstract: Porous organic polymers (POPs) both amorphous and crystalline represent an emerging class of nanoporous materials, and they feature robust covalent framework structures with high water and chemical stability. This, together with their high surface areas and tunable pore sizes, makes them hold promise for a variety of applications. We will demonstrate how POPs can be task-specific designed and functionalized via either de novel synthesis or stepwise post-synthetic modification for applications in water purification including oil spill cleanup, heavy metal removal, ion exchange, and nuclear waste treatment.