4-Aminobenzoic acid (also known as para-aminobenzoic acid or PABA because the two functional groups are attached to the benzene ring across from one another in the para position) is an organic compound with the formula H2NC6H4CO2H. PABA is a white crystalline solid, although commercial samples can appear gray. It is slightly soluble in water. It consists of a benzene ring substituted with amino and carboxyl groups. The compound occurs extensively in the natural world.4-Aminobenzoic acid, also known as PABA, with CAS number has a variety of applications. It’s used as a building block in the synthesis of various organic compounds, in the production of pharmaceuticals, as a sunscreen ingredient, and in medical treatments.