Five derivatives of Formazn (FM1–FM5) were prepared through reaction between benzaldehydphenylhydrazone with five diazonium salts by a reaction ratio of 1:1 in alkaline medium. The hydrazone was prepared through the reaction between phenylhydrazine and benzaldehydeby a reaction ratio of 1:1 in a slight acidic medium. Crystals of formazans resulting from recrystalization were formed by using different solvents and show variation of solubility among these formazans according to the kind of the solvent and the kind of diazonium salt used. Their purity was studied by using thin layer chromatography. The melting point of the prepared hydrazone and the resulting Formazan complexes were complexes with lead (II), copper(II) and cadmium were successfully prepared and studied by using UV and IR spectroscopy. These complexes were used as ionophors and applied as electrically active materials in the preparation of ion-selective membranes for the mentioned metal ions.