Second-order nonlinear optical (NLO) crystal materials are applied widely. In this work, a new benzothiazolium-based ionic organic NLO material (E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]thiazol-3-ium 4-methylbenzenesulfonate (DABT) containing strong electron donor and acceptor was designed and theoretically investigated. A simple approach that can be employed in rapidly and efficiently evaluating the second-order nonlinear properties of organic crystals based on its crystal structure information was also proposed. Results indicate that the as-designed DABT crystal possesses non-centrosymmetric structure with space group P2₁, and particularly, it exhibits a large static first-order hyperpolarizability of ∼117 × 10⁻³⁰ esu. Moreover, the optical properties of the DABT, including its permittivity, absorption coefficient, and reflectance, were systematically investigated, revealing that the DABT crystal is an anisotropic and a new and promising material with hydrophobicity and anisotropy, holding great potential applications in nonlinear optics.

二阶非线性光学（NLO）晶体材料应用广泛。在这项工作中，一种新的基于苯并噻唑的离子有机 NLO 材料 (E)-2-(4-(二甲基氨基)苯乙烯基)-3-甲基苯并[d]噻唑-3-ium 4-甲基苯磺酸盐 (DABT) 含有强电子供体和受体的设计和理论上的研究。还提出了一种可用于根据其晶体结构信息快速有效地评估有机晶体的二阶非线性特性的简单方法。_{结果表明，所设计的 DABT 晶体具有空间群 P2 1}的非中心对称结构，特别是它表现出 ~117 × 10 ^-30的大静态一阶超极化率 埃苏。此外，系统地研究了DABT的介电常数、吸收系数和反射率等光学性质，表明DABT晶体是一种各向异性的、具有疏水性和各向异性的新型材料，在非线性光学领域具有巨大的应用潜力。