<p>Achieving the second-order nonlinear optical (NLO) effect necessitates a non-centrosymmetric (NCS) structure, which is a prerequisite, but obtaining it effectively remains greatly challenging. In pursuit of this, a strategy known as “dimensionality elevation” has been operated to create a high-dimensional NCS framework based on a low-dimensional centrosymmetric (CS) structure. Concretely, the acentric [CdS₄] tetrahedral unit serves as a linkage point in the zero-dimensional (0D) [Si₄S₁₀] T2-supertetrahedra, leading to the formation of the 3D NCS rigid sulfide, Cs₂CdSi₄S₁₀ (<b>1</b>), which exhibits moderate second-harmonic generation (SHG) effect (0.5 × AgGaS₂@1.91 μm). To enhance the SHG coefficient, a structural modification has been made by replacing the Si-based framework with a Ga-based one and re-employing the “dimensionality elevation” strategy. This alteration prompted the tetrahedral [CdS₄] units to connect with 0D T2-supertetrahedral [Ga₄S₁₀] motifs, creating the 3D NCS salt-inclusion chalcogenide [Ba₄Cl₂][CdGa₄S₁₀] (<b>2</b>). Notably, compared with <b>1</b>, compound <b>2</b> not only demonstrates an increased SHG response (1.3 × AgGaS₂ @1.91 μm) but also retains a broad band gap (3.74 eV for <b>1</b> and 3.50 eV for <b>2</b>) for exceptional laser-induced damage thresholds (LIDTs, 9.3 × and 7.3 × AgGaS₂ @1.06 μm for <b>1</b> and <b>2</b>, respectively), suggesting that compound <b>2</b> is an advanced infrared NLO material. This research pioneers new pathways for discovering NCS NLO materials through the “dimensionality elevation” strategy.</p>