Strontium doped Cerium oxide (Ce1-0.25Sr0.25O2 nanocrystals were synthesized by combustion technique. The synthesized (Ce1-xSrxO2, x = 0.25, 0.5) nanocrystals were annealed at 500° C for 2hr. The phase formation, surface morphology and elemental composition analysis have been studied using XRD, HRSEM and EDXS. XRD and HRSEM measurements revealed that the synthesized nanocrystals were in single phase with face-centered cubic (fcc) structure and that the nano-grains had different sizes. Chemical composition was confirmed using EDXS. The UV-Vis spectroscopic studies revealed that as the Sr doping level increases, the band gap width increases from Eg = 2.9 eV to 2.95 eV. At the same time, the wavelength of maximum absorbance shifts from λabs = 285 to 300 nm. Further, PL studies were performed with excitation wavelength λ = 350 nm and two main emission peaks were observed at 415 and 437 nm respectively. TGA, DTA and DSC measurements were carried out to check the weight loss and the occurrence of endothermic/exothermic reactions. [ABSTRACT FROM AUTHOR]