In this article, we discuss the effects of lithium nanosheets on the structural, optical, dielectric and optical conductivity parameters of the MoO3 films. The nanosandwiching of Li layers between two layers of MoO3 of thicknesses larger than 20 nm induced the crystallization process of the amorphous MoO3. Namely, MoO3 thin films that are nanosandwiched with Li sheets of thicknesses larger than 50 nm, exhibit structural phase transitions from hexagonal to monoclinic and reveals larger crystallite sizes. The possible formation of Li2O at the MoO3/Li/MoO3 interfaces is simulated and discussed. Optically, the Li nanosandwiching is observed to enhance the light absorbability by 11.0 times at 2.0 eV and successfully engineered the energy bands gap in the range of 3.05–0.45 eV. It also enhances the dielectric performance. In addition, relatively thick layers of lithium (200 nm) succeeds in converting the conductivity type from n-to p-type. The modeling of the dielectric spectra in accordance with the Drude- Lorentz approach have shown that the presence of Li in the structure of MoO3 significantly increases the drift mobility values of electrons from 5.86 to 11.40 cm2/V. The plasmon frequency range for this system varies in the frequency domain of 0.32–5.94 GHz. The features of MoO3/Li/MoO3 interfaces make them attractive for thin film transistor technology as optical receivers being promising for use in optical communications.