Phosphorescent copolymers bearing a covalently linked charged platinum(II) dye were prepared using ring-opening metathesis polymerisation (ROMP). Absorption, emission as well as dynamic light scattering measurements of these polyelectrolytes indicate the formation of red luminescent aggregates in solution with quantum yields up to 17% and luminescence decay times in the range of 250-300 ns. Neither the quantum yield nor lifetime of the luminescence is affected by the presence of oxygen. The resulting polymers are solution processible and exhibit good film-forming properties. In contrast, the mononuclear platinum species are poorly soluble and non-luminescent at room temperature in deaerated solution. (C) 2011 Elsevier Ltd. All rights reserved.