Interlayer processes of porphyrin-fullerene dyad (PF) and octanethiol-protected 3 nm-gold nanoparticles (AuNP), assembled as films by Langmuir-Schafer method, were studied by fluorescence and photoelectrical measurements. The PF and AuNP films appear homogeneous on mu m-scale and have full coverage on each other. Both the exciplex emission and the photoelectrical response of the PF dyad are altered by the AuNP film. The results show that the AuNP film has an interaction with the intramolecular exciplex of the PF dyad. (C) 2009 Elsevier B. V. All rights reserved.