Dual-state efficient chromophore with pH-responsive and solvatofluorochromic properties based on an asymmetric single benzene framework.

We present a unique single-benzene-based chromophore with asymmetric structure that emits efficient luminescence in both solid and solution states and shows solvatofluorochromism, large Stokes shift (154-219 nm) and an extraordinary wide range of solvent compatibility. The asymmetric structural feature endows this chromophore with significant ratiometric pH-dependent fluorescence for accurate and fast pH sensing over a pH range from 4.0 to 8.2, which could be applied for visual identification of different brands of drinking water. It may find broad applications in environmental sensing and pH-associated physiological processes.