Used as a reagent in organic synthesis, particularly in Suzuki-Miyaura cross-coupling reactions. It serves as a stable source of the 4-ethylphenyl group, enabling its introduction into aromatic and heteroaromatic compounds via transition metal catalysis, typically with palladium. This is valuable in pharmaceutical and agrochemical development for building complex molecular architectures with enhanced properties. The trifluoroborate moiety provides hydrolytic stability compared to boronic acids, and the potassium counterion ensures good solubility in polar solvents, facilitating reactions under mild conditions. Commonly applied in late-stage functionalization of complex molecules to minimize side reactions and improve yields.