Heterojunction of hydrophobic poly(1,4-phenylenevinylene) (PPV) on hydrophilic CdS nanoparticles was successfully prepared by the multi-layering of poly(p-xylene tetrahydrothiophenium chloride) (pre-PPV: precursor of PPV polymer) and poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) in an aqueous solution followed by a thermal treatment. CdS nanoparticles thin films were prepared on tin-doped indium oxide (ITO) by a chemical-bath-deposition method. The CdS surface was hydrophilic with low water contact angle of 15 degrees. Positively charged and water-soluble pre-PPV was used to form multilayers with PEDOT:PSS by a layer-by-layer deposition method. Pre-PPV is easily converted to conjugated PPV polymer by a thermal treatment. The CdS nanoparticles-(PPV/PEDOT:PSS) multilayer films constitute efficient acceptor-sensitizer dyad systems, which generate a photocurrent of 2,660 nA/cm2 under the air mass (AM) 1.5 conditions (I=100 mW/cm2) for sample with 4.5 bilayers.