Communication: Polyvinylamine (PVAm) can be readily functionalized by means of a nucleophilic substitution reaction with 4-fluoro-substituted aromatic compounds having a substituent with negative mesomeric effect in ortho and/or para position. PVAm is soluble in water only in which aromatic fluoro compounds are usually sparingly soluble. However, the solubility of aromatic compounds in water can be mediated in particular by cyclodextrin derivatives. This first report on the nucleophilic substitution reaction of 4-fluoronitrobenzene with PVAm provides an elegant method towards the preparation of chromophoric water-soluble polymers by means of a one-pot procedure.