Nitrogen, chloride doped carbon dots (N, Cl-CDs) were synthesized in deep eutectic solvent. TEM, XRD, FT-IR, XPS, EDAX, UV–Vis and fluorescence were used for characterization. Quantum yield and average size of N, Cl-CDs were 38.75 % and 2–3 nm, respectively. N, Cl-CDs fluorescence was turn off by cobalt ion and then turn on gradually after addition of enrofloxacin. Linear dynamic range and detection limit (DL) for Co2+ and enrofloxacin were (0.1–70 µM and 30 nM) and (0.05–50 µM and 25 nM), respectively. Enrofloxacin was detected in blood serum and water samples with the recovery of 96–103 %. Finally, Antibacterial activity of the carbon dots was also investigated.
