1e:T409,Commercial photochromic and thermochromic colorants that change rapidly and reversibly from colorless to colored state when activated by stimuli like ultraviolet irradiation, temperature or pH are well established class of colorants for manufacturing of niche products. Use of photochromic and thermochromic systems in applications like medical thermography, plastic strip thermometers, photochromic lenses, food packaging and nondestructive testing of engineered articles and electronic circuitry is well documented. However, in the last few years, the research on application of these systems on textiles has picked up significantly which has the potential to unlock commercially significant nascent high-tech applications. This review paper presents a summary of the chemistry, mechanism, application on textiles and evaluation procedure of performance, other technical features, current and potential application areas as well as challenges encountered in wider acceptance of photochromic and thermochromic colorants on textiles.1f:T538,Health concerns as a result of harmful UV-rays drive the development of UV-sensors of different kinds. In this research, a UV-responsive smart textile is produced by inkjet printing and UV-LED curing of a specifically designed photochromic ink on PET fabric. This paper focuses on tuning and characterizing the colour performance of a photochromic dye embedded in a UV-curable ink resin. The influence of industrial fabrication parameters on the crosslinking density of the UV-resin and hence on the colour kinetics is investigated. A lower crosslinking density of the UV-resin increases the kinetic switching speed of the photochromic dye molecules upon isomerization. By introducing an extended kinetic model, which defines rate constants k _colouration, k _decay and k _{decolouration}, the colour performance of photochromic textiles can be predicted. Fabrication parameters present a flexible and fast alternative to polymer conjugation to control kinetics of photochromic dyes in a resin. In particular, industrial fabrication parameters during printing and curing of the photochromic ink are used to set the colour yield, colouration/decolouration rates and the durability, which are important characteristics towards the development of a UV-sensor for smart textile applications.20:T4aa,1,3,3‐Trimethylspiroindoline‐2,3′‐3 H ‐naphth[2,1‐ b ][1,4]oxazine ( 1a ) and 6′‐piperidino‐1,3,3‐trimethylspiroindoline‐2,3′‐3 H ‐naphth[2,1‐ b ][1,4]oxazine ( 1b ) were applied as disperse dyes to polyester, nylon and acrylic fabrics. Under optimised dyeing conditions, photochromic fabrics were produced which, on irradiation with ultraviolet or exposure to sunlight, turned blue ( 1a) or blueish‐purple ( 1b ). Dye 1a showed enhanced photochromic colour change performance compared with dye 1b . The photochromic colour build was highest on nylon and lowest on acrylic fabric. The colour change properties and the technical performance (wash fastness and photostability) of the photochromic fabrics were evaluated using specifically adapted colour measurement methods. The data were analysed in terms of variation of lightness, a *, b *, chroma, hue angle and Δ E , colour difference before and after exposure, and K / S curves as a function of irradiation time. The fabrics generally showed good wash fastness. Although the colour build‐up decreased with exposure to the Xenotest fadeometer, some residual photochromism remained after prolonged exposure.21:T517,Photochromic silica nanoparticles (SiO₂@NPT), fabricated through the covalent immobilization of silylated naphthopyrans (NPTs) based on 2H-naphtho[1,2-b]pyran (S1, S2) and 3H-naphtho[2,1-b]pyran (S3, S4) or through the direct adsorption of the parent naphthopyrans (1, 3) onto silica nanoparticles (SiO₂ NPs), were successfully incorporated onto cotton fabrics by a screen-printing process. Two aqueous acrylic- (AC-) and polyurethane- (PU-) based inks were used as dispersing me

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