Smart textiles consisting of cotton, Cu-BTC MOF and oxidized graphitic carbon nitride, g-C3N4-ox, nanospheres were synthesized and tested as nerve agent detoxification media and colorimetric detectors. Combining Cu-BTC and g-C3N4-ox resulted in a nanocomposite (MOFgCNox) of heterogeneous porosity and chemistry. Upon the deposition of MOFgCNox onto cotton textiles, a stable fabric with a supreme photocatalytic detoxification ability towards the nerve gas surrogate, dimethyl chlorophosphate, was obtained. The detoxification process was accompanied by a visible and gradual color change, which can be used for the selective detection of chemical warfare agents and for monitoring their penetration inside a protective layer. These smart textiles adsorbed almost 7 g of CWA surrogate/its detoxification products per gram of Cu. The superior performance was linked to the high dispersion of the MOF crystals on the fibers, and a specific texture promoting the availability of the active copper centers.