1,10-Phenanthroline entails several appealing structural and chemical properties: rigidity, planarity, aromaticity, basicity, chelating capability. This makes it a versatile starting material for synthetic organic, inorganic and supramolecular chemistry. In this tutorial review we examine how the chemical versatility of pristine 1,10-phenanthroline, a weakly fluorescent molecule, has been exploited to design many UV-Vis-NIR luminescent organic derivatives and coordination compounds with transition-metal (Ru(II), Os(II), Rh(III), Cr(III), Pt(II), Zn(II), Cu(I), Ag(I)) and rare-earth (Eu(III),Tb(III), Yb(III), Nd(III), Er(III)) cations. They are utilized for many analytical and technological applications.