Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah-711 103, West Bengal, India E-mail : akmahapatra@chem.iiests.ac.in Manuscript received 02 May 2017, accepted 08 May 2017 A new Hantzsch ester fluorescent probe (TPC) containing thienyl-pyridine group appended to the dihydropyridine ring was synthesized and characterized and successfully applied in the fluorescent sensing nitric oxide (NO) in aqueous solution. The fluorescence of probe TPC shows extremely strong blue fluorescent, while its fluorescence was greatly switched off upon the addition of NO solution and showed high selectivity and sensitivity to NO. The limit of the detection was calculated to be ~0.4 µM. A reaction mechanism for dihydropyridine with NO is proposed in this study. The probe shows good stability over a broad pH range (pH > 4). The structure of the TPC probe has been established by single-crystal XRD. DFT and TDDFT calculations were done to demonstrate the electronic properties of the probe and the corresponding aromatic product. Moreover, the utility of the TPC probe in detecting NO in live cells has also been demonstrated using Raw 264.7 cells as monitored by fluorescence imaging.