Measure what is measurable, and make measurable what is not so! This timeless quotation by Galileo forms the basis of all quantitative understanding, including asymmetric organocatalysis. We report pKa values for 15 chiral Brønsted acid catalysts in DMSO solutions (see scheme): the strongest acids were bis‐sulfonyl/sulfuryl imides (pKa=1.7–1.9) followed by phosphoric acids/amides (pKa=2.4–4.2). A new class of chiral Brønsted acids, tetrakis‐perfluoroalkyl analogues of TADDOLs (TEFDDOLs) have pKas from 2.4 to 5.7.

We herein present the first synthesis of 1,1′‐binaphthyl‐2,2′‐bis(sulfuryl)imides (JINGLEs). This new class of chiral Brønsted acids was synthesized in one step from the corresponding BINOLs and imidobis(sulfuryl chloride). A total of six enantiopure 1,1′‐binaphthyl‐2,2′‐bis(sulfuryl)imides, carrying different 3,3′‐substituents, were synthesized and characterized, inter alia, by X‐ray crystallography.