A novel monoanionic tetradentate N4 ligand (F 5 DPPy) based on a dipyrromethene skeleton as a molecular platform and decorated with pyridine rings at the 1-and 9-positions of the dipyrrin motif has been prepared and characterized. Interestingly, although this ligand is weakly fluorescent, it presents a chelation-enhanced fluorescence effect of around 150 times upon coordination to Zn II . Time-dependent (TD) DFT calculations reproduce nicely the spectroscopic features of both [a]