A new bis-heteroleptic Ru-II complex (1[PF6](2)) with iodotriazole as the anion binding group along with the attached pyrene moiety is developed to investigate anion sensing properties and the origin of its selectivity toward a particular class of anions. Selective sensing of phosphates over other anions in both the solution and solid states by 1[PF6](2) is clearly evident from the perturbation of the absorption band and a large degree of amplification of (MLCT)-M-3 emission band in the presence of phosphates. Importantly, macroscopic investigation such as Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS) indicated the formation of supramolecular architecture in the presence of dihydrogen phosphate via halogen bonding interaction and pi-pi stacking of pyrene moieties. Such macroscopic property is further corroborated by solution and solid state spectroscopic studies, e.g., H-1-DOSY NMR, single crystal X-ray crystallography, and solid state photoluminescence (PL) spectroscopy.