An ICT-based highly fluorescent isoquinoline scaffold for selective Hg(II) detection in real-water samples: Development of a smart, low-cost RGB-Arduino electronic platform

•A novel isoquinoline-based highly tunable fluorescent probe, IQ was reported.•It displayed robust sensing ability towards Hg2+ ions in nearly aqueous solution.•Comparative FT-IR, 1H/13C NMR, mass spectral, and DFT studies were performed.•Real sample analysis was performed by detecting mercury in varied water sources.•An RGB-arduino electronic device was fabricated facilitating real-time analysis.