The Z-scan and DFT techniques were explored to investigate the non-linear optical properties of anthraquinone fused imidazole-based D-π-A dyes. With the help of UV–visible spectral analysis, pH study, CV analysis, HOMO-LUMO interaction, MEP plots, and quinoidal character the influence of intramolecular charge transfer characteristics and H-bonding process on electronic and photophysical studies of anthraquinone derivatives were understood. The dyes 2-(4-(diethylamino)-2-hydroxyphenyl)-3H-anthra[1,2-d]imidazole-6,11-dione (AQ1) and 2-(2-hydroxynaphthalen-1-yl)-1H-anthra[1,2-d]imidazole-6,11-dione (AQ2) displayed a single emission with pronounced Stokes shift and thermal stability (upto 290 °C). The dye AQ1 exhibited strong charge transfer character which is explained by the ICT process leading to high nonlinear susceptibility χ⁽³⁾ in AQ1 3.43 × 10⁻¹³ e.s.u relative to the dye AQ2 which has only ESIPT core. But, the dye AQ2 6.27 J cm⁻² showed better optical limiting value. The NLO properties of AQ1 and AQ2 were computed by DFT functionals based on Hartree Fork (HF) percentage exchange. The dye AQ1 exhibits noticeable NLO properties. The global hybrid functionals with HF composition beyond 50% (BHHLYP, M06-HF) and the long rang corrected functionals (CAM-B3LYP, ωB97, and ωB97X) demonstrated comparable NLO properties relative to B3LYP and PBE0. It was observed that the combined effect of ICT and the H-bonding cores enhance the NLO properties. The experimental findings (Z-scan) were successfully correlated with theoretical (DFT) results.

的ž〜扫描和DFT技术进行了探讨研究蒽醌稠合咪唑系d-π-A染料的非线性光学特性。借助紫外可见光谱分析，pH研究，CV分析，HOMO-LUMO相互作用，MEP图和喹诺酮特性，可以了解分子内电荷转移特性和氢键过程对蒽醌衍生物的电子和光物理研究的影响。染料2-（4-（二乙基氨基）-2-羟基苯基）-3H-蒽[1,2- d ]咪唑-6,11-二酮（AQ1）和2-（2-羟基萘-1-基）-1H -anthra [1,2- d]咪唑-6,11-二酮（AQ2）表现出单一的发射，具有明显的斯托克斯位移和热稳定性（最高290°C）。染料AQ1表现出较强的电荷转移特性，这是由ICT过程解释的，相对于仅具有ESIPT核心的染料AQ2，其导致AQ1 3.43×10 ^-13 esu中的高非线性磁化率χ ^（3）。但是，染料AQ2 6.27 J cm ^-2显示出更好的光学极限值。通过基于Hartree Fork（HF）百分比交换的DFT功能，计算AQ1和AQ2的NLO属性。染料AQ1具有明显的NLO性能。HF成分超过50％（BHHLYP，M06-HF）和远程校正功能（CAM-B3LYP，ωB97和ωB97X）的全局混合功能展示了与B3LYP和PBE0相当的NLO性能。据观察，ICT和氢键核心的共同作用增强了NLO性能。实验结果（Z扫描）已成功与理论（DFT）结果相关。