Thin film of ethane bridged Zn-Porphyrin dimers is deposited via Langmuir-Schäfer (LS) technique over Au/Co/Au transducers properly realized on glass substrates. They have been tested as sensing layers in the novel Magneto-Optical Surface Plasmon Resonance (MO-SPR) sensor for monitoring the controlled adsorption of molecules of a volatile compound such as tert-butylamine vapours. The sensing performance of the organic layer onto the novel MO-SPR transductor sensor has been evaluated.