Abstract: The present invention relates to a method for covalently binding a first agent and a second agent, the first agent comprising a first recognition element, wherein the first recognition element comprises an 1,4-dioxo moiety having a structure of Formula IA, IB or IC, wherein R12 is C1-30alkyl, C2-30alkenyl, C6-15aryl, or C5-15heteroaryl, wherein the C1-30alkyl, C2-30alkenyl, C6-15aryl, or C5-15heteroaryl group are optionally substituted with an C1-6alkyl, C3-6cycloalkyl, halogen, amine, hydroxyl, sulfhydryl, carboxyl, or C1-6alkoxy; and R13, if present, is hydrogen, C1-30alkyl or C2-30alkenyl; the second agent comprising a second recognition element, wherein the second recognition element comprises a nucleophilic moiety selected from a hydrazine moiety, an aminooxy moiety, an aminosulfanyl moiety or a hydroxylamine moiety; wherein: (A) the first recognition element and the second recognition element are capable of non-covalently binding to each other such that the 1,4-dioxo moiety and the nucleophilic moiety a