The steady-state and non equilibrium photoexcitation dynamics of semiconducting polymer nanospheres is studied in detail and compared to a regular bulk film of the same polymer (methyl-substituted ladder-type poly(para)phenylene). It is found that the major optical properties of the polymer are left unaltered by this innovative material processing approach. However there is a clear influence of the film nanostructure on the generation, migration and recombination behavior of the involved photoexcited species. (C) 2004 Elsevier B.V. All rights reserved.