The present disclosure provides a method for preparing a radioactive ligand or radioactive substrate having affinity for a target biomacromolecule, the method comprising: (a) reacting a first compound comprising a first functional group capable of participating in a click chemistry reaction, with a radioactive reagent under conditions sufficient to displace the leaving group with a radioactive component of the radioactive reagent to form a first radioactive compound; (b) providing a second compound comprising a second complementary functional group capable of participating in a click chemistry reaction with the first functional group; (c) reacting the first functional group of the first radioactive compound with the complementary functional group of the second compound via a click chemistry reaction to form the radioactive ligand or substrate; and (d) isolating the radioactive ligand or substrate.