摘要： Dual mode Nanosensors gained tremendous interest in recent years because of their facile synthesis and dual applications. Herein we have synthesized highly fluorescent carbon dots (CDs) from Mahogany fruit shell by chemical oxidation method. The as prepared CDs exhibited selective and sensitive quenching of fluorescence by Fe3+ and also accompanied by a dramatic increase in absorption intensity. Hence these two processes led to fabricate CDs-Fe3+ system as a dual probe. D-Penicillamine (D-PA) has much affinity toward Fe3+ which resulted in recovery of almost 75% fluorescence intensity and decrease in absorption of the CDs-Fe3+ system. Thus, this tendency has been exploited for the selective detection of D-PA by both Spectrofluorimetrically and UV-Visible spectroscopically and showed a wide linear range of detection 0-48 μg mL?1 respectively. This developed probe offered low cost, high selectivity, repeatability, facile operation and excellent recovery ratio in detection of D-PA in pharmaceutical samples. Moreover, biological applications CDs were investigated using Saccharomyces cerevisiae strain with confocal microscopy. We found that CDs were a biocompatible and ideal candidate for differential staining of yeast cells.