The crucial involvement of amino acids in various physiological processes and their ability to function as effective biomarkers for a variety of diseased conditions has inspired a significant activity in conceptualizing sensor system for amino acids, although there are still limited reports which aim to detect basic amino acids with simpler design yet with high sensitivity and selectivity. Herein, we report a ratiometric optical sensor that is based on Arginine and Lysine-induced disintegration of a supramolecular assembly, leading to significant modulation in the monomer-aggregate equilibrium, which yields a ratiometric signal that has been used for quantification of Lysine and Arginine in aqueous solutions. Our sensor design overcomes many disadvantages that are associated with the existing optical sensing schemes, such as, technically demanding and time-consuming synthetic protocols for probe synthesis, limited aqueous solubility, and more importantly, most of the previously reported sensors operate via single wavelength based measurements, which makes their performance error prone to a variety of analyte-independent factors which can be overcome by ratiometric detection as achieved here. Overall, we have devised a label free, rapid, simple, dual-sensing, ratiometric sensor for the detection of basic amino acids. Importantly, our sensing system also shows response in the human serum matrix.