In this work, the results of a new method for the preparation of porous silicon (PS) layers with in situ simultaneous functionalization with organic molecules are reported. The molecules of interest are dissolved in the HF ethanoic solution used to prepare the PS layers by partial anodic dissolution of a Si electrode. The method has been proved to be effective with various molecules. In this Communication, the case of PS functionalization with heptyne molecules, studied by FTIR spectroscopy, is reported in detail. The results demonstrate that this new functionalization method, accompanied by a low-level oxidation, is simple, fast, and effective and that it can allow the confinement of the adsorbed molecules selectively in a single layer of a PS stack.