Synthesis of heavy metal cation sensing molecules based on 0-Phenylenediamine. It possesses conjugate property, and push-pull system. It can be a good Organic Light Emitting Diode. We employ 0-Phenylenediamine’s amino group to synthetize a good binding site. Finally, we titrate with solution which include heavy metal cation following measure the maximum UV- Vis wavelength. We observe color change