Valacyclovir (VAL), as a prodrug to acyclovir antiviral agent, has recently held a lot of interest for its efficacy boosting owing to the significant improvement in bioavailability. This makes it a successful candidate in the management of herpes simplex strains as well as CORONA viruses. In this work a carbon nano dot-modified glassy carbon electrode (GCE) has been optimized as potentiometric sensor for the assay of VAL through a systematic approach. A mixture components of polyvinyl chloride (PVC) membrane have been selected and fine-tuned for optimum sensitivity and selectivity. The best results have been obtained by drop casting a blend in % w/w of PVC; 30.85, tricrasyl phosphate (TCP) as plasticizer; 64.32, phosphotungstic acid (PT) as cation exchanger; 1.61 and phosphorus – nitrogen-doped carbon nano-dots (PNCDs); 3.22 over the GCE. The density function theory (DFT) calculations have been applied …