Lewis acids are crucial in chemistry with applications in pharmaceuticals, agrochemicals, and materials science. In main-group chemistry, they offer alternatives to transition metals, prompting our study on halogenated boronic acid esters (BAEs). Although BAEs are well-known, their catalytic potential has been overlooked. Our investigation found their Lewis acidity superior to boron trifluoride and comparable to tris(pentafluorophenyl)borane. Additionally, their catalysis of the Sakurai allylation of aldehydes is documented, paving the way for future advancements.