 Abstract CUNP2S6, CIPPS, is a promising material for applications such as ferroelectrics and thermoelectrics. SIPPS exhibits a large remnant polarization at ambient conditions, but this value decreases significantly when subjected to hydrostatic pressure. We investigated the effect of pressure on the structural and electronic properties of CIPPS and found that the initial decrease in polarization is caused by the suppression of the crystalline distortions of the Cucat ions. This is followed by a gradual increase in polarization due to the condensation of Cucat ions into the interlayer sites, which is further enhanced by the cell volume reduction. At higher pressures, the migration of Cucat ions to the center of the S octahedra causes a decrease in polarization. Our results provide insight into the mechanism behind the pressure-induced changes in the structural and electronic properties of CIPPS and suggest strategies to optimize its performance. This article was offered by Xiaodong Yao, Yinxin Bai, Cheng Jin, and others. We are article.tv, links in the description below.