In the present work, we have carried out an extensive investigation on the high pressure structural, mechanical and thermal properties of some rare earth chalcogenides and pnictides using interionic potential method with modified ionic charge parameter, which include the effect of Coulomb screening at ambient and at high pressure. The structural properties cover the structural phase transition, cohesive energy, bulk modulus and lattice constants of some rare earth chalcogenide and pnictide compounds. Upon the application of certain amount of pressure on the materials they undergo structural change, which is one of the fascinating properties found in the materials. By considering the structural data mechanical and thermal properties have been calculated. We hope that our findings will be the exciting future and a good chance that they could play a role in the technological and fundamental developments that will inevitably appear in the field of materials science and the new results contained here will contribute to these advances.