A poly(ionic liquid) (BA-PIL) carrying a benzoic acid group in each repeating unit of the polymer architecture, which has the dual function of acting as a matrix and second ligand, has been developed. Through the incorporation of BA-PIL with the complex [Ln(hfa)3 ] (hfa=hexafluoroacetylacetone) as an emitting precursor, significant luminescence improvement was achieved in the obtained hybrid materials. Confinement of the lanthanide(III) complexes within the rigid chains of the polymer, together with replacement of the coordinated water molecules, are believed to be ascribed to the enhanced optical properties.