Redox-active compounds and uses thereof

A redox flow battery, comprising a substituted low molecular weight aromatic compound or a composition comprising the compound, wherein the compound is characterized by any one of General Formulas (1)-(2):

• wherein,
• each R1-R8 in General Formula (1),
• each R1-R10 in General Formula (2),
• is independently selected from
• —H, -Alkyl, -AlkylGa, -Aryl, —SO3H, —SO3−, —SO3H/—SO3−, —PO3H2, —OH, —OGa, —SH, -Amine, —NH2, —CHO, —COOH, —COOGa, —CN, —CONH2, —CONHGa, —CONGa2, -Heteroaryl, -Heterocycyl, NOGa, —N+OGa, —F, —Cl, and —Br,
• or
• are joined together to form a saturated or an unsaturated carbocycle,
• wherein the saturated or the unsaturated carbocycle is —H, -Alkyl, -AlkylGa, —SO3H/—SO3−, OGa, or —COOH;
• wherein each Ga is independently selected from
• H, -Alkyl, -AlkylGb,-Aryl, —SO3H, —SO3−, —PO3H2, —OH, —OAlkyl, —OOH, —OOAlkyl, —SH, —SAlkyl, —NH2, —NHAlkyl, —NAlkyl2, —NAlkyl3+, —NHGb, —NGb2, —NGb3+, —CHO, —COOH, —COOAlkyl, —CN, —CONH2, —CONHAlkyl, —CONAlkyl2, -Heteroaryl, -Heterocycyl, —NOGb, —N+OAlkyl, —F, —Cl, and —Br;
• wherein each Gb is independently selected from
• —H, -Alkyl, -Aryl, —SO3H, —SO3−, —PO3H2, —OH, —OAlkyl, —OOH, —OOAlkyl, —SH, —SAlkyl, —NH2, —NHAlkyl, —NAlkyl2, —NAlkyl3+, —CHO, —COOH, —COOAlkyl, —CN, —CONH2, —CONHAlkyl, —CONAlkyl2, -Heteroaryl, -Heterocycyl, —N+OAlkyl, —F, —Cl, and —Br;
• and
• wherein at least one substituent is a methyl group and at least one other substituent is selected from alkoxy, amine, carboxyl, sulfonyl, and hydroxyl.