“…[20,21] Near-infrared luminescence from Nd III , Dy III , Er III , Tm III , and Yb III is also sensitized by dipicolinate moieties, [9,22,23] although usually to a lesser extent than visible emission. For all these reasons, this family of complexes was used in several applications, such as various inorganic-organic hybrid materials, [24] nanoparticles, [25] or as analytical probes, particularly for the analysis of bacterial spores [26][27][28] or of nanomolar concentrations of Tb III . [29] Finally, lanthanide dipicolinates display nonlinear optical (NLO) properties [30,31] and two-photon excitation luminescence, either through an allowed Tb III f-f transition [32] or through the ligand, [33,34] enabling luminescence microscopy images to be collected under NIR excitation.…”