Four dicarboxylic chelates (MAL, SUC, ADP, and SUP) were employed to explore the effect of (CH2) extension on extraction efficiency of the corresponding dicarboxylates for Hg(II), Cd(II), and pb(II) ions. Binding effectiveness (extraction efficiency) for the forementioned ions was determined by measuring the percent of extraction.The efficiency of extraction was found to depend on number of (CH2) units within the chelate. This result was deduced after correlating the extraction efficiency with the number of (CH2) units in the diacid chelate. Parameters like charge density distribution and HOMO energy were found to support the proceeded conclusion.