“…We note that many lanthanide‐doped nanomaterials have been largely exploited as bioimaging agent but not as theranostic agents [24,25] . In this regard, few lanthanide‐based nanoparticles are explored as theranostic vehicles, for example, core‐shell structured NaLuF 4 nanorods@polydopamine, [5] Gd/Eu‐doped ZnO NPs, [6] lanthanum oxyiodide (LaOI) nanosheets, [8] polyacrylic acid (PAA)‐functionalized porous BiF 3 :Yb,Er, [9] NaLnF 4 @MOF−Ln nanocomposites, [10] zwitterionic gadolinium(III) (Gd(III))‐complexed dendrimer‐entrapped gold nanoparticles, [11] etc. Though the above reports show promising results, most of the studies are in the preliminary level and they face the following challenges:(1) do not possess targeting ability, (2) limited drug loading, (3) extensive surface chemistry to conjugate the drug, which can affect the photoluminescence properties, (4) lack of information regarding in vitro, immuno‐compatibility and in vivo toxicity, (5) lack of information regarding bio‐distribution and targeting efficiency and (6) use of high concentration for in vivo imaging.…”