Luminescence of a ladder-type methyl-poly(para-phenylene) (MeLPPP) doped with 5% (by weight) platinum-porphyrin (PtOEP) has been investigated. It is shown that upon exciting in the spectral range of absorption of the guest the delayed fluorescence of the polymer is observed. Based upon field quenching of delayed fluorescence it is argued that it originates from an exciplex between PtOEP and MeLPPP generated by exciting the S-1 state of PtOEP. (C) 2003 Elsevier B.V. All rights reserved.