4-Aryl-6-phenylpyrimidin-2 (1H)-ones were synthesised via a three-component one-pot cyclocondensation of aromatic aldehyde, acetophenone and urea catalysed by 0.2 ml (0.024 mol%) of concentration HCl in ionic liquid [BMIM][BF4]. The fluorescence properties of product and partial products' efficient sensing of zinc ion were studied in detail. The structure of 4, 6-diphenylpyrimidin-2 (1H)-one was confirmed by X-ray analysis.