 The study presents the successful synthesis of five new non-centrosymmetric lanthanide selenides with strong second harmonic generation, SHG, using partial fluorination of the lanthanide oxygen polyhedron and an HF corrosion resistant supercritical hydrothermal method. The compounds exhibit a novel 3D framework composed of 1D molybdenum selenide chains bridged by LN2F2012, OH2, dimers, with SHG responses ranging from 1.0 to 9.0 times KH2PO4, KDP, at 1064 nanometers and up to 1.2 times KTP, KTPO4, at 2050 nanometers for the half-filled GD compound. These compounds also possess excellent physical chemical stability and strong luminescence emission, making them promising multifunctional non-linear optical materials. The study offers an effective way for designing and synthesizing high-performance non-linear optical materials. This article was authored by Yun Siong Ma, Ping Feili, Chunli Hu, and others. We are article.tv, links in the description below.