In this study, we focus on structural, electronic, elastic, lattice dynamic and optic properties of MgGeP2 and MgGeAs2 using ab-initio density-functional theory (DFT) within Armiento-Mattson 2005 (AM05) scheme of the generalized gradient approximation (GGA) for the exchange-correlation potential. Our computed structural results are in reasonable agreement with the literature. The band gap of these compounds is predicted to be direct. Our elastic results prove that these compounds are mechanically stable. The obtained phonon spectra of MgGeP2 and MgGeAs2 do not exhibit any significant imaginary branches using GGA-AM05 for the exchange-correlation approximation. Further analysis of the optical response of the dielectric functions, optical reflectivity, refractive index, extinction coefficient and electron energy loss delves into for the energy range of 0-22.5 eV. It motivated that there exists an optical polarization anisotropy of these compounds for optoelectronic device applications. (C) 2016 Elsevier Ltd. All rights reserved.