Thermodynamic data referring to a new homologous series of fluorinated alkoxy-benzylidene-anilines are presented. Phase diagrams show the presence of smectic A and/or B phases determined by thermal microscopy and X-ray diffraction techniques. Interdigitated structures are not present in these smectic phases. Trends in clearing temperatures are briefly discussed in comparison with those for thep-alkoxy-benzylidene-p'-alkoxy-anilines in order to clarify the role of the fluorine atom.