GaPS4 is a 2D auxetic material with exotic mechanical and optical properties. In 2D form, it exhibits negative Poisson’s ratio both in-plane and out-of-plane directions. Bulk GaPS4 is a direct wide gap semiconductor with the computed band gap values of 2.1 and 3.2 eV depending on the functionals used while the experimental data is needed to confirm. Our GaPS4 crystals have been synthesized using vapor transport technique (CVT) to achieve high purity 99.99995% and electronic/mechanical/optical quality.