AbstractFunctionalization of polysulfones by using “Click” chemistry is described for the example of a small fluorescent analyte propargylpyrene. First, PSUs were converted to azido‐functionalized polymers by successive chloromethylation and azidation. Propargylpyrene was prepared independently as a fluorescent click component. Finally, the azido‐functionalized PSUs were coupled with propargylpyrene with high efficiency by copper‐catalyzed azide/alkyne click reactions. The final polymers and intermediates at various stages were characterized by 1H NMR, FT‐IR, GPC, UV‐Vis, and fluorescence spectroscopy techniques. magnified image