Building block for synthesis. DPA is a secondary amine with two picolyl substituents. The compound is a tridentate ligand in coordination chemistry and commonly used to produce Zn-based chemosensors/probes, such as Zinpry. As a tridentate ligand this compound provides three nitrogen donors that affords good selectivity for Zn2+ over biologically relevant metals such as Na+, K+, Mg2+ and Ca2+, and leaves coordination sites free for anion binding. The amino nitrogen of the DPA group is a good candidate as an electron donor in either photoinduced electron transfer or photoinduced charge transfer (PET or PCT) sensors. Zn(II)–DPA complexes are widely used in anion recognition and sensing.