Abstract: The present invention relates to compounds that are two-part molecules, and compositions containing such compounds, in which one part is designed to become covalently bonded to the skin (bonding agent) and the other part (a characteristic use agent) is designed to impart some characteristic use, such as emolliency, moisturizing effect, anti-acne, anti-wrinkle, anti-pain, antimicrobial, antifungal, antiviral, anti-irritation, skin tanning and skin lightening effects, extended protection of the skin (e.g., from ultraviolet light, by incorporation of a sunscreen component; from toxic and/or irritating substances; from insects and skin parasites, by incorporation of insecticides and/or insect repellants; from free radicals or other agents, as in aging, by incorporation of antioxidants), or dyeing of hair, skin nails, wool or fur. The covalently bonded part may also be useful to impart skin strengthening effect (e.g., from shear forces) or as wound healing agents.