In this work, a D–π–A based coumarin–pyridone conjugate (CPC) was synthesised by a one-pot multicomponent reaction and the structure was proven from infrared and nuclear magnetic resonance spectroscopies and high-resolution mass spectrometry. Quantum chemical parameters and molecular electrostatic potential were assessed using DFT investigations. CPC exhibited absorption and emission spectra in the ranges 451–460 nm and 532–549 nm, respectively, and also exhibited positive solvatochromic behavior. It was employed as a fluorescent labeling agent for the visualization of latent fingerprints (LFPs) on various surfaces. LFPs visualized by CPC exhibited information from level-I to level-III LFPs, with low background interference, and high sensitivity and selectivity. The electrochemical sensitivity and reliable detections of nitrite (NO₂⁻) in neutral PBS (pH = 7) electrolyte solution was investigated. It was found that the cyclic voltammetry (CV) and chrono-amperometric (CA) oxidation current at 0.60 V (applied potential 0.50 V) by a modified CPC/GC electrode exhibit good sensitivity and detection. Under optimum conditions, a lower detection limit for CV; 10 nM and CA; 7.5 nM (at an S/N ratio of 3) was achieved. A CPC/GC electrode based nitrite sensor also displays good selectivity in the presence of interference molecules such as ascorbic acid, dopamine, uric acid, paracetamol and glucose.