 The design of new materials with special performances remains a major challenge, particularly when it comes to DPV non-linear optical materials. It is difficult to achieve a balance between large band gaps and strong second harmonic generation responses due to their inverse relationship. Cation variation can influence both the overall structure and electronic structure leading to unpredictable material performance. To address this issue, a novel approach was developed to characterize the role of cations. This approach was used to explore the effects of cation variation on the properties of borate materials. Several borate series were tested and the result showed that barium substitution for lead leads to a blue shift in the ultraviolet cutoff edge while maintaining a strong second harmonic generation response. This strategy can be applied to optimize the properties of DPV non-linear optical materials, making them more efficient in fluoro-oxperates. Furthermore, the cation characterization method developed here can help guide material design and selection. This article was authored by Tsonghu, Meng Cheng, Wenqi Jin, and others. We are article.tv, links in the description below.