Recent advancements in the chemistry of 1,3,4-Thiadiazole ring-containing azo dyes

The chemistry of 1,3,4-thiadiazole-based azo dyes has attracted significant attention owing to their structural versatility, enhanced stability, and multifunctional applications across textiles, biomedicine, and advanced materials. This review consolidates recent progress in synthetic strategies, electronic tailoring, and structure–activity relationships of thiadiazole-appended azo derivatives, with a focus on their photophysical, antimicrobial, anticancer, optical properties, and textile application. Special emphasis is given to green synthetic routes—such as solvent-free, microwave-assisted, and ionic liquid-mediated protocols—that align with sustainability goals while overcoming limitations of conventional dye synthesis. The role of thiadiazole moieties in modulating electronic effects, promoting intramolecular charge transfer, and enabling strong metal coordination is critically examined, highlighting their impact on improved color strength, fastness, and functional bioactivity. Computational approaches, including DFT, molecular docking, and ADMET predictions, are discussed as powerful tools to bridge experimental and theoretical insights, offering predictive frameworks for dye performance and toxicity. Furthermore, the emerging applications of these dyes in sensors, organic electronics, and renewable energy devices underscore their potential beyond traditional coloration. Despite challenges in scalability, standardization, and predictive modeling, interdisciplinary innovations promise to establish thiadiazole-based azo dyes as next-generation sustainable colorants and functional materials. • Comprehensive synthesis routes for 1,3,4-thiadiazole azo dyes, highlighting green and sustainable methods. • Structure–property relationships analyzed using DFT and molecular dynamics simulations. • Thiadiazole moiety enables improved photophysical and electronic dye properties. • Multifunctional uses in textiles, sensors, antimicrobial materials, and optoelectronics. • Key challenges and future directions for scalable, eco-friendly, smart dye systems.