This theoretical study is performed to investigate structural, elastic, and electronic properties as well as optical response to incident photons of thallium based chloroperovskite TlXCl3 (X = Ca and Cd) compounds. Both compounds have a stable crystal structure with optimized lattice constants ranging from 5.40 Å to 5.26 Å. The elastic parameters such as elastic constants, bulk modulus, anisotropy factor, Poisson’s ratio, and Pugh’s ratio are evaluated. Poisson’s ratio describes the ductile nature of these materials. The band structure and elemental contribution to different states for all the compounds are analyzed. Materials have a wide bandgap with indirect band nature. Optical parameters such as dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, and optical conductivity are studied in the energy range of 0 eV–30 eV. The comparative results suggest that thallium based compounds are important to be used as scintillating materials and stimulate further experimental investigations of such compounds.
