C-nitroso compounds and their complexes with transition metals have never been used before in Langmuir experiments. Some isotherms have been registered for several C-nitroso derivatives and for two metal complexes with Pd(II) and Rh(I) thin films were deposited by the standard vertical dipping method, UV-Vis spectroscopy has been performed in order to analyse the absorption bands of the deposited films. Measurements of the dependence of the conductivity were carried out between 300 and 450 K. All samples display an activated conductivity at high temperature and related activation energies were determined. A decrease of the activation energy is reported for the palladium complex thin films into a flux of air and ppm NO2.