Methods of treating, preventing or suppressing symptoms associated with mitochondrial diseases, such as Friedreich's ataxia (FRDA), Leber's Hereditary Optic Neuropathy (LHON), dominant optic atrophy (DOA)； mitochondrial myopathy, encephalopathy, lactacidosis, stroke (MELAS), Leigh syndrome or Kearns-Sayre Syndrome (KSS) with compounds of Formula (I) are disclosed. Methods of modulating, normalizing, or enhancing energy biomarkers, as well as compounds useful for such methods are also disclosed.
