Department of Analytical Chemistry, Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai-600 025, India E-mail: kvenkatchemisty@gmail.com Manuscript received online 01 September 2018, accepted 09 October 2018 In this study, synthesis of highly luminescent carbon dots (CDs) is one of the hot research areas in the present-day context C-dots synthesis from Moringa oleifera gum is a green materials. The C-dots synthesis using hydrothermal method using 180ºC for 24 h reaction. We have synthesized highly luminescent CDs in a green way which can be adopted for large-scale production of luminescent CDs. In the newly synthesized C-dots characterizations including UV-Vis, FT-IR, Raman, PL and FE-SEM etc. The newly prepared CCPE was using C-dots and potentiometric heavy toxic metal ions sensing. We have demonstrated the CDs as a sensitive and selective potentiometric sensor for the determination of Hg2+ ions which is a well-known environmental toxic pollutant.