Smart pyrene-based simple fluorescent probes 2 and 4 were designed, synthesized and characterized by different spectroscopic methods. The photophysical properties of the probes and their affinity towards different metal ions in phosphate buffer were investigated. Upon selective interaction with Hg²⁺, the molecular probes showed enhanced static excimer emission at 506 nm along with a naked-eye detectable chromo- and fluoro-genic response. Probe 2 sensitively showed a high limit of detection (3.4 pM) for Hg²⁺ in the solution. The pyrene silicate derivative, 4, was utilized to detect and extract Hg²⁺ in solution as well as in the solid state. The data obtained from NMR and ESI-MS spectroscopy supported the postulate that the mode of interaction of the probe with Hg²⁺ involves the N and O atoms of the –CN and –OH functional groups to complex Hg²⁺ in 2 : 1 stoichiometry. Moreover, probe 2 exhibited excellent selectivity for Hg²⁺ in protein medium (BSA/HSA) and was used to detect Hg²⁺ in live HeLa cells, on test paper strips and in real contaminated water samples.