Visible luminescence europium(iii) complexes with large π-conjugated systems were theoretically and experimentally studied. A strategy for extending the π-conjugation of a ligand for use with europium(iii) ions was found on the basis of fragment molecular orbital and density functional theory calculations. Using this method, a novel europium complex was designed and synthesized. Its excited state properties were assessed from the luminescence spectrum, excitation spectrum, luminescence lifetime, and luminescence quantum yield. In this study, the novel photophysics induced by the combination of visible luminescent europium(iii) ions and large π-conjugated systems are described.