Diphosphate compounds (KYP₂O₇) co-doped with Yb³⁺ and Er³⁺ ions were obtained by one step urea assisted combustion synthesis. The experimental parameters of synthesis were optimized using an experimental design approach related to co-dopants concentration and heattreatment as well as annealing time. The obtained materials were studied with theinitial requirements showing appropriate morphological (X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM)) and spectroscopic properties (emission, luminescence kinetics). Moreover, the effect of Er³⁺ and Yb³⁺ ions doped KYP₂O₇ on morphology, proliferative and metabolic activity and apoptosis in MC3T3-E1 osteoblast cell line and 4B12osteoclasts cell line was investigated. Furthermore, the expression of the common pro-osteogenic markers in MC3T3-E1 osteoblast as well as osteoclastogenesis related markers in 4B12 osteoclasts was evaluated. The extensive in vitro studies showed that KYP₂O₇ doped with 1 mol% Er³⁺ and 20 mol% Yb³⁺ ions positively affected the MC3T3-E1 and 4B12 cells activity without triggering their apoptosis. Moreover, it was shown that an activation of mTOR and Pi3k signaling pathways with 1 mol% Er³⁺, 20 mol% Yb³⁺: KYP₂O₇ can promote the MC3T3-E1 cells expression of late osteogenic markers including RUNX and BMP-2. The obtained data shed a promising light for KYP₂O₇ doped with Er³⁺ and Yb³⁺ ions as a potential factors improving bone fracture healing as well as in bioimaging (so-called in theranostics).