Cobalt tetracarbonyl dimer is primarily used in organic synthesis as a catalyst. It plays a crucial role in carbonylation reactions, where it facilitates the addition of carbon monoxide to organic compounds. This is particularly useful in the production of aldehydes, ketones, and carboxylic acids. Additionally, it is employed in hydroformylation processes, which are essential for manufacturing alcohols and other derivatives in the chemical industry. Its ability to act as a source of cobalt in various catalytic systems makes it valuable in the development of pharmaceuticals, fine chemicals, and polymers.