AbstractFive novel aminomethylphosphinic acid ligands (L1–L5) have been synthesized and characterized. The pH-potentiometric technique was used for determining the dissociation constants (pK) of the compounds. The stabilizing ability of complexes of a novel chiral ligand of bis(aminomethyl)phosphinic acid (L1) with transition metals such as Co2+, Ni2+, Zn2+, Fe2+, Cu2+, Cd2+ and lanthanide ions La3+