Description Mitochondria perform several functions in the cell, and dysfunction has been implicated in various organ systems and disease states, including neurodegenerative disorders and cancers. The targeting of small molecules to the mitochondria can help to probe and better understand this relationship. This bromohexane triphenylphosphine (TPP) tag is conjugated to small molecules to localize them to the mitochondria in cells where the TPP cations facilitate both cellular uptake and accumulation in the mitochondria.