A new ditopic ion pair receptor 1 containing two biindole moieties and a bis-benzocrown ether unit shows a remarkable color switching (ON- and -OFF) function induced by anion (F−) and cation (K+) recognition. The ditopic receptor 1 binds in a cooperative fashion to HSO4− in the presence of 1·K+ and acts as a selective ditopic receptor to recognize ion pairs with a wavelength-ratiometric manner.Highlights► 1 shows high selectivity for detecting F− in color change and spectra change. ► 1 functions as a chromogenic molecular switch by using combinations of F− and K+. ► 1 shows high selectivity for detecting HSO4− by the naked eye in 1·K+ complex. ► 1 shows selectivity for detecting HSO4− in ratiometric manner in 1·K+ complex. ► Titration experiment of 1 with HSO4− in case of K+ shows enhancement of affinities.