The structural, elastic, electronic, optical, and thermodynamic properties of the $$\hbox {ZnAl}_{2}\hbox {S}_{4 }$$ ZnAl 2 S 4 compound are calculated in the frame work of the density functional theory where the calculated structural parameters are found to be in good agreement with the experimental data and other theoretical calculations. The calculations show that the material is elastically stable and isotropic. Furthermore, the calculated band gap is observed to be wide and direct and is comparable with earlier experimental data as well as with other theoretical calculations; hence, it is an optically active material for optoelectronic applications. In addition, the compound is found to have mixed ionic and covalent bonding nature. The optical nature of the compound is described in terms of the complex dielectric function, complex refractive index, reflectivity, and energy loss function. On the other hand, variation of the unit cell volume, bulk modulus, heat capacity, and Debye temperature are described as a function of temperature at different pressures for the $$\hbox {ZnAl}_{2}\hbox {S}_{4}$$ ZnAl 2 S 4 compound.