Abstract The manipulation of pressure and structural composition can result in tuned properties of a material to enhance its functionality. In this regard, the pressure significance of the ternary Cd 0.75 Zn 0.25 S alloy is acknowledged in this study by changing in the range of 0–20 GPa using density functional theory (DFT) via a self‐consistent field within a generalized gradient approximation (GGA) and GGA–modified Becke–Jhonson (mBJ). The results demonstrate that this ternary alloy exhibits cubic symmetry at all operating pressures, with the bandgap energy increasing from 2.81 to 3.17 eV as the pressure increases, demonstrating that it is a direct bandgap alloy. Another aspect of this study pertains to the optical parameters of the material and their variations as a function of pressure. Here it is observed that absorption increases with increasing pressure, along with the static refractive index and static dielectric constant. As optical conductance is also increased, the findings of this study offer a theoretical framework for the Cd 0.75 Zn 0.25 S alloy for display applications in optoelectronic and photovoltaic devices operating at various pressure ranges.