Non-centrosymmetric (NCS) structure is an indispensable prerequisite for second-order nonlinear optical (NLO) material. Currently, the mainstream approach for designing new NCS structures still relies on chemical substitution, necessitating an urgent infusion of fresh ideas. In this work, two isomorphic sulfides AeMn₆Ga₆S₁₆ (Ae = Ca, 1; Sr, 2) are afforded by modifying the skeleton of centrosymmetric (CS) Mn₂Ga₂S₅ via introducing strong electropositive alkaline-earth cations. Concretely, the incorporation of Ca²⁺/Sr²⁺ cations allows the elementary [MnGaS₉]_∞ chains to reconfigure into bumpy [MnS₆]-[GaS₄] layers in a new engagement manner, thus enabling the conversion from CS to NCS structure. Such modifications cause not only strong second-harmonic generation (SHG) responses (∼1.5 × benchmark AgGaS₂ @1,700 nm), but also significantly feasible bandgaps (2.60–2.64 eV) compared to the sulfide Mn₂Ga₂S₅ (1.36 eV), which ultimately facilitate ultrahigh laser-induced damage thresholds (4.4–6.6 × AgGaS₂ @1,064 nm for compounds 1 and 2). The present study offers an ingenious approach for the transformation of CS to NCS structure.

非中心对称（NCS）结构是二阶非线性光学（NLO）材料不可或缺的先决条件。目前，设计新型NCS结构的主流方法仍然依赖于化学替代，迫切需要注入新的想法。在这项工作中，通过修饰中心对称的骨架，得到了两种同晶硫化物 AeMn ₆ Ga ₆ S ₁₆ (Ae = Ca, 1; Sr, 2) (CS) Mn ₂ Ga ₂ S ₅ 通过引入强电正性碱土金属阳离子。具体来说，Ca ²⁺ /Sr ²⁺ 阳离子的掺入使得基本 [MnGaS ₉ ] _∞ 链重新配置成凹凸不平的 [MnS ₆ ]-[GaS ₄ ]以新的接合方式层，从而实现从CS结构到NCS结构的转换。与硫化物 Mn ₂ Ga ₂ S ₅ (1.36 eV)，最终促进超高激光诱导损伤阈值 (4.4–6.6 × AgGaS ₂ @1,064 nm（化合物 1 和 2））。本研究为 CS 向 NCS 结构的转变提供了一种巧妙的方法。