In the last decades, many scientific publications have focused on upconverting nanoparticles (UCNPs) doped with lanthanide ions due to their applicable potential. The upconversion (UC) phenomenon is based on the absorption of low-energy photons (from the near-infrared region) to produce higher-energy anti-Stokes luminescence. [1]. This study examines how the structural disorders caused by replacing Ca2+ ions with Sr2+ ions in host matrice influence the spectroscopic properties of Ca1-xSrxF2 nanoparticles doped with lanthanide ions synthesized by a simple one-pot hydrothermal synthesis assisted with microwave. The physicochemical properties of Ca1-xSrxF2 nanomaterials were investigated by different methods, among others, XRD and spectroscopic measurements (emission spectra, luminescence decays, power dependence of the upconversion emission intensity on excitation power).