Adenine, thymine and uracil thio‐derived acyclonucleosides were synthesized and characterized by UV‐Vis, FT‐IR, 1H and 13C NMR spectroscopic techniques. The photophysical properties of the derivatives were evaluated in solvents with diverse polarities and at various pH values. The solvent dependent absorbance and emission spectral shifts were analysed using physical parameters of the selected solvents. The regression and correlation coefficients were calculated using multiple regression techniques. The fitting coefficients gave an estimate of the contribution of each interaction to the total spectral shift in various solutions. Multiple linear regression studies, Kamlet‐Taft equation and stokes shift correlation with orientation polarizability provide valuable information concerning spectroscopic characteristics of the studied molecules. A multi-functional “turn-off” fluorescent probe, N-[[(6-Amino-1,2,3,4-tetrahydro-1,3-dimethyl-2,4-dioxo-5-pyrimidinyl)amino]thioxomethyl]- benzamide, was synthesized and characterized. The probe showed high sensitivity and selectivity towards copper(II), iron(III) and silver(I) ions via quenching of its fluorescence. The detection limits were found to be 4.0 – 16.0 ppb for the assayedcations. The thiourea linked uracil fluorescent probe is proved to be sensitive, selective, applicable in real samples and promise for practical applications.