The engineering of a complete adlayer of organic nanolines by supramolecular self-assembly has been achieved for the first time on a silicon-based surface at room temperature and has been studied by scanning tunneling microscopy. This complete adlayer has been successfully obtained thanks to the combination of a specific Si(1 1 1)-B root 3x root 3R30 degrees semiconductive surface and of strong hydrogen bonds between a pair of dipolar molecules.