Sulfanilic acid (SA) is a typical representative compound of sulfonated aromatic amines and an intermediate in some sulfonated azo dyes. Sulfanilic acid is used as an intermediate compound in the chemical industry for the production of dyes, pesticides, detergents and sulfonamides.

Studies have reported that sulfanilic acid can also be used as  a highly functional cross-linking agent improves the mechanical properties of gels. On the one hand, SA is a water-soluble small molecule, which makes it easier to be dispersed uniformly in the gel network. The water-soluble and small molecules can overcome the problem of uneven cross-linking distribution in the internal network of the gel, which helps to construct a uniform topological network of the gel; on the other hand, multiple hydrogen bonds can be established between SA molecules and PAM chains, and different energy dissipation modes can be established in PAM/SA gels. Therefore, the uniform topology and efficient energy dissipation process can be established in the gel network synergistically, which provides a strong platform for the gel to withstand stress, dissipate energy and rebuild the network during deformation, and thus improves the mechanical properties of PAM/SA gels, especially the fatigue resistance.

Sulfanilic acid is also used as a reagent in analytical chemistry and as an additive in construction materials and food. As well as being used in the paper, pulp, cardboard and polymer industries, among others. However, sulfonated aromatic amines are toxic to humans, so researchers isolated a strain of bacteria with the ability to degrade sulfanilic acid. The bacterial strain, identified as Ochrobactrum anthrop, can utilise sulphamic acid as its sole carbon and energy source.