In this research, the aluminate spinel type materials, MAl2O4, are synthesised by solution combustion synthesis (SCS) method to investigate the effect of the element (M = Ca and Ba) on their structural, mainly crystallinity and optical properties. The characterisations are examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and UV-visible diffuse reflectance spectroscopy (UV-DRS). The XRD and FT-IR results showed the formation of the single-phase spinel structure of CaAl2O4 and BaAl2O4. The band gap energy was investigated using the Tauc method, and the obtained values were 3.93 eV and 3.77 eV for CaAl2O4 and BaAl2O4, respectively. The results showed a good agreement with the data as reported in the literature.