The stock solution of R1 (1 × 10−3 mol L−1) as well as the anions as their tetrabutylammonium salts (F−, Cl−, Br−, I−, ClO4 −, H2PO4 −,and AcO−) solutions (1 × 10−3 mol L−1) were prepared in DMSO and then the prepared anions were taken in different equivalents and added to R1 and their corresponding UV–visible and Fluorescence spectra were recorded at 298 K