NOVELTY - Substituting (M1) polyaromatic hydrocarbons or polyheterocyclic compounds with perfluoroalkyl groups involves: heating polyaromatic hydrocarbon substrate or a polyheterocyclic compound substrate in presence of perfluoroalkyl iodide, in optionally closed reaction system to bring both polyaromatic hydrocarbons or polyheterocyclic compound, and perfluoroalkyl iodide, into gas phase, thereby allowing substrate to react with perfluoroalkyl iodide in gas phase to form polyaromatic hydrocarbons or polyheterocyclic compounds having at least one perfluoroalkyl substituent.    USE - For substituting polyaromatic hydrocarbons or polyheterocyclic compounds with perfluoroalkyl groups (claimed) useful as important building blocks and active components in biomedical, electronic, and materials applications.    ADVANTAGE - The methods allow for the creation of versatile libraries of novel perfluoroalkyl-containing derivatives that can serve as important building blocks and active components in biomedical, electronic, and materials applications. The method can be carried out in a single step by combining reactants in the gas phase to provide new compounds with unprecedented substitution patterns. The method is solvent-free and therefore very environmentally friendly.    DETAILED DESCRIPTION - Substituting (M1) polyaromatic hydrocarbons or polyheterocyclic compounds with perfluoroalkyl groups involves: heating a polyaromatic hydrocarbon substrate or a polyheterocyclic compound substrate in the presence of a perfluoroalkyl iodide, in an optionally closed reaction system, where the heating is to bring both the polyaromatic hydrocarbons or polyheterocyclic compound, and the perfluoroalkyl iodide, into the gas phase, thereby allowing the substrate to react with the perfluoroalkyl iodide in the gas phase to form polyaromatic hydrocarbons or polyheterocyclic compounds having at least one perfluoroalkyl substituent. An INDEPENDENT CLAIM is included for a compound prepared by the method (M1).