A pyrene-based simple fluorosensor has been synthesized by a one step process. It exhibited high selectivity towards Cu(2+) ions via fluorescence enhancement of monomer and excimer emission. The origin of excimer formation was examined and established to be of static in nature from the study of absorption and excitation spectra. The observed monomer and excimer emission in the presence and absence of Cu(2+) ion with varying pH was studied and provided probable justification. The effect of varying portions of water content in solvent on the sensor molecule was also examined. The sensor found its proper application in finding accurate and trace amount of Cu(2+) ions present in drinking water samples from various sources. The detection limit of the current sensor was found to be 4 × 10(-8) M.