End-capped Poly(ethylene oxide)s have been synthesized starting from PEO and two different PPV monomers. The modification reactions lead to Poly(ethylene oxide)-block-Poly(para-phenylene vinylene) precursor copolymers which can be converted, in the reaction medium, to the di-block copolymers with a conjugated chain. The latter were characterised by Fluorimetry and Size Exclusion Chromatography.