We report a new method to control both the nucleation and growth of polypyrrole (Ppy) for the formation of the patterns from micrometer to nanometer sizes using adsorbed sodium dodecyl sulfate bilayers as a molecular mask. Polystyrene (PS) and poly(4-vinylpyridine) blend and block poly(styrene-b-4-vinylpyridine), which have microphase-separated domains in micrometer and nanometer scales, respectively, were used as templates. With the molecular mask, the resulting Ppy can be selectively grown. up to 50 nm only along the PS domains.