<p>The effects of transition metal substitution on the structural, electronic, magnetic, mechanical, and lattice dynamical properties of CePd₂In₄ and CePt₂In₄ intermetallic compounds were systematically investigated using first-principles calculations within the generalized gradient approximation. This work constitutes the first comprehensive theoretical study of these materials. The calculated lattice parameters are in agreement with available experimental data. The mechanical stability of both compounds is confirmed as their second-order elastic constants satisfy the Born stability criteria. Furthermore, phonon dispersion calculations reveal no imaginary frequencies throughout the Brillouin zone, confirming the dynamical stability of both compounds. Analysis of the mechanical properties revealed significant elastic anisotropy. Electronic structure calculations indicate metallic behaviour arising from the overlap between valence and conduction bands. The combination of high average atomic mass and relatively weak bond strength leads to low Debye temperatures and low thermal conductivity. The estimated melting temperatures are relatively high for both compounds, indicating their suitability for high-temperature applications. These findings suggest that CePd₂In₄ and CePt₂In₄ compounds may be promising candidates for high-temperature and thermal control applications.</p>