Using the sol-gel method, we elaborated the La1-xCaxNi0.5Ti0.5O3 (x=0.0 and x=0.2) nanopowders. These powders were sintered at 820°C. X-ray diffraction technique (DRX) and Fourier transform infrared spectroscopy (FTIR) verify the formation of a perovskite orthorhombic structure with the Pnma space group. The band gap energy was evaluated by UV–Vis spectroscopy for the compounds. Photoluminescence (PL) explains the process by which a substance absorbs photons and then re-emits photons. It is found that the imaginary part of the modulus (M'') are frequency-related, and display relaxation peaks that shift to higher frequencies with rising temperature. A non-Debye relaxation was confirmed in our samples. We have improved permittivity with the calcium substitution rate. We found giant permittivity around 106. The value of the giant dielectric constant decreases with rising frequency, demonstrates that there is dispersion in the range of low-frequency and exhibit Maxwell-Wagner interface polarization. We computed the activation energy from the dielectric constant and the modulus (M). The observed giant permittivity values specify that our materials may be appropriate for applications in energy storage devices and small-volume high-performance capacitors.