The compounds 1-naphthyliminoferrocene{,} 1{,} and 2-methyl-1-naphthyliminoferrocene{,} 2{,} were prepared by the reaction of ferrocenecarboxaldehyde and the corresponding amine{,} 1-naphthylamine and 2-methyl-1-naphthylamine with one drop of pyrrolidine as catalyst{,} in CH2Cl2{,} under inert atmosphere. The compounds were fully characterized by elemental analyses{,} matrix-assisted laser desorption/ionization - time-of-flight mass spectrometry (MALDI-TOF){,} FT-IR{,} 1H and 13C NMR as well as two-dimensional{,} NOESY{,} COSY and HSQC{,} NMR spectroscopy. Mossbauer spectroscopic studies were performed to characterize the iron species in both compounds. The solid-state molecular structures of compounds 1 and 2 were determined by single crystal X-ray diffraction. Analysis of the electrochemical behaviour of complexes 1 and 2 was performed by cyclic and square wave voltammetry. Compounds 1 and 2 were tested as chromogenic and electrochemical sensors for Hg2+.