A compound that includes a quaterrylene dye moiety as core, and a dendrimeric shell. For example, the compound may comprise at least four dendronized polyamides covalently attached to a quaterrylene dye. Also disclosed is a compound, or a pharmaceutically acceptable salt or ester thereof, comprising A(G)x, wherein:A comprises a quaterrylene dyeG comprises at least one functionalized dendrimeric structure andx is 2 to 16.The compounds may be used for in methods for monitoring a therapeutic or diagnostic agent in a subject, or for treating a subject by administering the compound to the subject.
