Carbon Dots (CDs) are a course of carbon nanomaterials just under 10 nm in dimension endowed with signature optical and electronic properties finding applications in sensors, photocatalysis, biomedical as well as optoelectronics. Single stroke hydrothermal synthesis method seems to have been adopted as the generation of nanocarbon dots from the Indian medicinal plant, Plectranthus amboinicus. Advanced characterisation methods such as UV- Visible absorption spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy and HR TEM study have been adopted to confirm the structure of carbon nanoparticles. The dependence on the excitation of photoluminescence emission behaviour of CDs have been confirmed using PL spectroscopy. The reaction between the many metal ions with the photoluminescence of CDs are studied and found a striking interaction with Fe (III) ions. The equation from Stern-Volmer is used to study the mechanism of extinction involved in the sensing action of carbon dots and the threshold for recognition is found to be 0.30 μM. The existence of surface functional groups leading to the complexation with Fe (III) ions can primarily be the reason for the observed sensing application. The design and development of eco-friendly sensor systems for Iron metal which is also considered as an essential mineral for human health for its application in biomedical and environmental applications is discussed in this paper.