A series of poly(methyl methacrylate-co-9-anthryl methyl methacrylate) was prepared in which the anthryl groups were interspersed between each 2, 4, 10, 25 and 35 methyl methacrylate mers. The effect of the proximity of the chromophores in the photophysical properties was studied in dilute and concentrated conditions, showing that the association of anthryl groups giving rise to aggregates or excimers is strongly dependent of the chain conformations. The photophysical properties of cast-films of largely spaced copolymers are characterized by two decays: one of the isolated chromophore (longer decay rate and vibronically structured emission) and another of aggregated species (faster decay with some broadening of the red-edge of the emission band). Copolymers having the chromophores separated by two or four methyl methacrylate units presented the highest degree of association and were the only electroluminescent materials. The proximity of anthryl moieties and the conformation of the polymer chains are important factors governing excimeric-like emission and film properties of anthracene containing polymers used in technological applications. (C) 2003 Elsevier B.V. All rights reserved.29741699177186