Polysulfones are an important class of high performance commercial polymers with high heat tolerance, excellent mechanical properties, and good resistance to chemicals and most radiation sources. Key applications include membranes for hemodialysis and water purification; medical devices, including cases and trays; food contact applications; plumbing; and electronics such as mobile devices. These polymers are generally prepared through a condensation reaction between 4,4′-dichlorodiphenylsulfone (DCDPS) and an aromatic diol: bisphenol A (Bis A) in the case of polysulfone, bisphenol S (Bis S) for polyethersulfone, and biphenol for polyphenylsulfone. Their thermal stability imparts processability through traditional molding and extrusion operations. Polysulfones can be modified by blending with polymers and other additives commonly used in the plastics industry. Commercial grades exist with glass and carbon fibers to improve mechanical properties; with additives to impart improved thermo-oxidative behavior, photochemical resistance, or processability; with pigments and dyes to make a myriad of transparent and opaque colors; and polymer or monomer derived from postconsumer materials for improved sustainability. A large variety of novel polysulfones have been synthesized and proposed for various membrane applications. Most notable among these are variants with sulfonate pendant groups introduced either on one of the monomers used for polymerization or using a variety of “post-sulfonation” techniques. Polysulfone chemistry offers a platform to address some of the key challenges facing humanity today.