5-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)indolin-2-one, with CAS number 837392-64-0, is an organic compound featuring an indolin-2-one core structure substituted with a pinacol boronate ester group at the 5-position. This structure combines a heterocyclic scaffold (oxindole) with a versatile boron functional group, making it a valuable synthetic intermediate. This compound is primarily utilized as a key building block in medicinal chemistry and pharmaceutical research. The oxindole moiety is a privileged scaffold found in numerous bioactive molecules and drugs. The boronate ester group enables crucial carbon-carbon bond-forming reactions, most notably the Suzuki-Miyaura cross-coupling reaction. This allows for the efficient introduction of the oxindole fragment into more complex molecular architectures, facilitating the synthesis of potential drug candidates, particularly in the discovery of kinase inhibitors and other therapeutic agents. As a bifunctional reagent, it serves both as a specialized pharmaceutical intermediate and a versatile organoboron synthon in organic synthesis. Its application is central to constructing diverse compound libraries for biological screening and optimizing lead structures in drug development programs.