(Z)-6-(2-((2-Chloroquinolin-3-yl)methylene)hydrazineyl)-N2,N4-dicyclohexyl-1,3,5-triazine-2,4-diammine (SBL), was synthesized and characterized using various spectroscopic techniques. The structure was characterized by 1H NMR, 13C NMR, MS and IR spectroscopy. To study its fluorescence and colorimetric properties towards various metal ions, high sensitivity and selectivity were achieved for Co2+ over other common metal ions. The limit of detection (LOD) for Co²⁺ determination was found to be as low as 0.22 µM by fluorescence spectroscopy and 0.73 µM by UV–Vis spectroscopy, demonstrating the high sensitivity of the synthesized SBL receptor toward Co²⁺ ions. The 1:1 binding stoichiometry between receptor (1) and Co (II) ion was established using Job’s plot. The sensing mechanism is attributed to the coordination of Co²⁺ ions through the quinoline nitrogen, azomethine nitrogen, hydrazone nitrogen, and triazine nitrogen donor centers of the receptor, resulting in suppression of the PET process and enhancement of fluorescence emission. Complexation suppresses the photo-induced electron transfer (PET) process, resulting in a significant change in fluorescence intensity.