Core level photoemission studies have been performed on the in situ interactions of Cr and Cu on two model systems which are related to the pyromellitic dianhydride (PMDA) and oxydianiline (ODA) parts of PMDA–ODA polymide. The model compound which is related to the PMDA constituent is N,N′-diphenylpyromellitimide and the model polymer which is related to the ODA constituent is poly(2,6-dimethylphenylene oxide) (PMPO). Cr evaporation on the PMDA model compound changes the PMDA-related features of the C 1s spectrum, whereas Cu evaporation has comparatively little effect on the PMDA-related features. The results are consistent with Cr bonding with the PMDA part of the related model compound, or fracturing of the carbonyl bonds and/or other bonds contained in the PMDA structure. Cr evaporation on PMPO results in a new peak at lower binding energy without appreciable changes in the shape of the original bands. Cu predominantly affects the peak in the C 1s spectrum of PMPO which originates from carbons in ether linkages.