Tri-n-butyltin bromide is primarily used as a reagent and intermediate in organic synthesis, particularly in organotin chemistry for preparing other organotin compounds and facilitating reactions such as radical additions and transmetallation processes. It serves as a source of the tributylstannyl group in the synthesis of fine chemicals and materials. Due to its role in specialized applications, it is considered a specialty chemical. Handle with extreme caution as it is highly toxic, bioaccumulative, and has significant environmental impacts; many tributyltin compounds are restricted or banned in certain uses.