Phenethylmagnesium chloride is widely used in organic synthesis as a Grignard reagent. It plays a crucial role in forming carbon-carbon bonds, making it valuable for creating complex organic molecules. It is often employed in the preparation of alcohols, ketones, and carboxylic acids through reactions with carbonyl compounds like aldehydes, esters, and carbon dioxide. Additionally, it is utilized in pharmaceutical research for synthesizing intermediates in drug development. Its ability to act as a nucleophile makes it a versatile tool in constructing various organic structures.