The introduction of negatively charged 1-pyreneacetate anion into positively charged poly-L-lysine (P(Lys)) as a polymeric scaffold through electrostatic interactions, wherein the conformational change of the polypeptide was controlled, was allowed to induce the tuning of the fluorescence of the pyrene in aqueous media. Poly(L-glutamic acid) (P(Glu)) bearing multiple negatively charged side chains was also used to serve as a polymeric scaffold for the aggregation of positively charged 1-pyrenemethylammonium cation.