Abstract: A fiber is provided as a substrate for a functional nanostructure (coated fiber), composed of (a) a fiber substrate; (b) a reactive dye conjugating moiety covalently bound to the fiber substrate; (c) a bonding agent covalently bound to the reactive dye conjugating moiety; and (d) the functional nanostructure bound to the bonding agent. A method of making the coated fiber is also provided, involving the following steps in any order: covalently binding the reactive dye conjugating moiety to the fiber; covalently binding a bonding agent to the reactive dye conjugating moiety; and binding the functional nanostructure to the bonding agent. The nanostructures are tenaciously attached to the fibers, resisting very rough treatments, and can be made using inexpensive and widely available reactive dyes under non-stringent synthesis conditions.