Eu³⁺ and Tb³⁺ complexes based on an organo-alkoxysilane derived from 4-azido dipicolinic acid by “click chemistry” were coated onto silica nanoparticles previously prepared by the water in oil emulsion method. Structural and optical properties of the resulting luminescent core–shell monodisperse (30 nm) nanohybrids were fully characterized by infrared and Raman spectroscopies as well as by electron microscopy. Fluorescence spectroscopy evidenced that an efficient ligand-to-Ln³⁺ energy transfer—both in the mono- and biphotonic modes—occurs. Furthermore, surface modification by amino groups was realized, paving the way for nanotags of biological interest.