In this work, the structural, mech., and vibrational properties of CO2-V have been investigated by employing first-principles DFT calculations It is shown, for the first time, that the CO2-V single crystal has the potential to exhibit a neg. Poisson′s ratio for loading in all directions in the (001) plane in the pressure range 40-60 GPa. It is also shown that the Poisson′s ratio of CO2-V is pressure-dependent, with an increase in pressure resulting in an increase in the auxetic potential of the system. The auxetic behavior of this system has been analyzed by studying its deformation under the application of stress through both two-dimensional and three-dimensional approaches. From a two-dimensional perspective, the auxeticity of CO2-V can be explained by the relative rotation of semi-rigid projected squares, which both rotate and deform upon application of a stress. As the hydrostatic pressure is increased, the rigidity of the units increases, resulting in less deformation of the squares and hence an increase in auxetic potential. From a three-dimensional perspective, the auxetic behavior of CO2-V can be rationalised in terms of the interplay between relative rotation of CO4 tetrahedra, coupled with stretching and deformation of these CO4 units. All of this is very significant, as it enhances the corpus of knowledge on the mech. properties of a high-pressure polymorph of CO2, a substance that plays a significant role in planetary science.