Pyrrole-based anion-responsive π-electronic molecules as fluorescence sensors responsive to multiple stimuli.

Introduction of electron-donating N,N-dimethylaminophenyl groups in dipyrrolyldiketone BF2 complexes as anion-responsive π-electronic molecules resulted in fascinating fluorescence properties. The fluorescence properties, which depended on the degree of photo-induced electron transfer, could be controlled by solvent polarity, anion binding and protonation.