Blends of poly(p-phenylenebenzo[1,2-d:5,4-d’]bisoxazole) (PBO) dispersed in poly(ether ether ketone) (PEEK) have been prepared by casting and coagulating methanesulfonic acid (MSA) solutions containing different fractions of each polymer. At PBO fractions greater than about 1%, the fluorescence spectra resemble that of ’bulk’ PBO coagulates; but at lower PBO concentrations, the spectra show a sharper, blue-shifted peak, close to the 0-0 peak of dilute PBO/MSA. This emission most likely originates from PBO chains that have been isolated in a photophysical sense. This result, along with the solvent shift seen in a model compound, suggests that the deprotonation minimally perturbs the emission spectrum of PBO relative to the changes caused by aggregation.