...Here we have designed a library of alkyl-monoquaternary ammonium-triphenyl phosphine (TPP) and alkyl-diquaternary ammo-nium-TPP of varying alkyl chain lengths, which target the mitochondria; we also studied their senolytic properties. It was observed that the alkyl-diquaternary ammonium-TPP with the longest chain length induces apoptosis to senescent cells selectively via an increase of reactive oxygen species (ROS) and mitochondrial membrane disruption. This study demonstrated that mitochondria could be a potential target for designing new small molecules as senolytic agents for the treatment of a variety of dysfunctions associated with pathological aging.