The B–N bond controls the balance between locally excited (LE) and twisted internal charge transfer (TICT) states observed for aniline based fluorescent saccharide sensors

Three boronic acid based saccharide sensors with an aniline fluorophore have been prepared. One of the systems (1a) contains an intramolecular boron–nitrogen (B–N) bond and displays fluorescence due to both LE and TICT states. The other two systems (1b and c) have no B–N bond and only show fluorescence due to the LE state.