Isatoic anhydride derivatives having an N-substituent which includes a quaternary ammonium group are useful for labeling and/or functionalizing a target material and/or for coupling materials together. The isatoic anhydride derivatives of the present disclosure can be advantageously water soluble, easily prepared and purified. Isatoic anhydride derivatives useful in the present disclosure preferably have at least one chemically reactive group or at least one binding group or at least one detectable label. Anthranilate derivatives made from the isatoic anhydrides derivatives or otherwise and kits including the isatoic anhydride derivatives are also disclosed.
