A series of mitochondria targeted α-aminophosphonates combining a diethoxyphosphoryl group and an alkyl chain-connected triphenylphosphonium bromide tail were designed and synthesized, and their pH-sensitive 31P NMR properties and biological activities in vitro and in vivo were evaluated. The results showed a number of these mito-aminophosphonates exhibiting p K a values fitting the mitochondrial pH range, short relaxation, and chemical ...