S-3,3'-Bis(phenyl)-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate, commonly known as (S)-VAPOL phosphoric acid, is a chiral Brønsted acid catalyst derived from the VAPOL (vaulted biaryl phosphoric acid) ligand scaffold. Its structure features a rigid, axially chiral 1,1'-binaphthyl core with phenyl substituents at the 3,3'-positions and a phosphoric acid group at the 2,2'-positions, which serves as the active catalytic site. This compound is a prominent member of chiral phosphoric acids (CPAs) and is extensively used as an organocatalyst in asymmetric synthesis. It facilitates a wide range of enantioselective transformations, including but not limited to, Friedel-Crafts alkylations, Pictet-Spengler reactions, transfer hydrogenations, and various cycloaddition reactions. Its primary application lies in constructing chiral centers for pharmaceuticals and advanced organic materials by activating substrates through hydrogen-bonding or ion-pairing interactions. As a specialized, high-value chiral auxiliary, it is not a general-purpose synthetic building block but a dedicated catalyst precursor. Its development and use are pivotal in academic research and industrial process development for enantioselective catalysis, contributing significantly to the synthesis of optically active compounds.