Initially the ionophoretic technique was limited for separation purpose in Biology and chemistry. In 1964, the Jokl extended it to the qualitative study of simple Inorganic complexes. Now the techniques has been proved as a handy tool for the study of coordination compounds in solution. Authors research group has successfully and widely applied electrophoretic method with drastic modifications to the quantitative assessment of equilibrium constants of some inorganic complexation reactions. The present work reports some of our obser vations for Th (IV), Fe (III), Cr (III) and A1 (III)- Cysteine complexes.