Natural dyes as multifunctional sustainable materials: from green extraction to analytical, energy, and smart textile applications

Natural dyes are emerging as multifunctional sustainable materials for green analytical chemistry, renewable energy, smart packaging, and functional textiles. However, existing reviews focus on isolated aspects, leaving a gap for an integrated assessment covering the entire value chain from green extraction to end‐of‐life management. This review critically overviews plant‐ and waste‐derived pigments as nontoxic chromogenic reagents for spectrophotometric determination of Fe 3+ , Cu 2+ , Al 3+ , Ni 2+ , and Co 2+ , exploiting the chelation chemistry of polyphenols, anthocyanins, and curcuminoids. We examine green extraction techniques (deep eutectic solvents, ultrasound and microwave‐assisted extraction) alongside validated analytical performance metrics (UHPLC‐PDA‐HRMS, with limits of detection down to 0.024 ppm). We also evaluate natural dyes as photosensitizers in dye‐sensitized solar cells (DSSCs), where plant‐mediated green synthesis of TiO 2 nanoparticles offers an eco–friendly route, albeit with power conversion efficiencies (1–4%) substantially below those of synthetic sensitizers (11–13%). Additionally, we cover pH‐responsive dyes (anthocyanins, shikonin) for real‐time food freshness monitoring and antimicrobial functional textiles. Natural dyes are not yet universal replacements for synthetic colorants in high‐performance applications, but they offer compelling alternatives for routine analytical chemistry, educational laboratories, low‐cost sensors, and products where biodegradability and safety outweigh performance. We identify three research priorities: stability enhancement (copigmentation, encapsulation), circular sensor design (covalent immobilization, composting), and standardization of analytical protocols. Our findings provide a decision framework for selecting natural dyes based on trade‐offs between cost, stability, and environmental impact.