p-Conjugated polymers for organic electronic applications are often designed to aggregate or crystallize to enhance their charge carrier mobility. Their electronic properties often improve with increasing molecular weight. Determining the molecular weight of these polymers via size-exclusion chromatography (SEC), however, is complicated due to their significant aggregation in solution. We demonstrate that superheated high-temperature SEC with chloroform as the mobile phase, operated at temperatures well above the normal boiling point of the solvent, can effectively be used to determine the molecular weight for these polymers by dissolving the aggregates. © 2014 The Royal Society of Chemistry.