Cytokine and growth factor receptors play crucial roles in signaling cascades that modulate cell survival, adhesion, proliferation, and migration. Because the dynamic behaviors of these receptors are highly related to their functions and to changes in ligand-dependent signals, reliable techniques for visualization of these receptors are strongly desired. Here, we have developed a method of covalently and tracelessly labeling membrane receptors in live cells by using chemically reactive cytokines and growth factors coupled with an organocatalyst that facilitates a selective acyl transfer reaction on the target receptors. Construction of the reactive cytokines and growth factors relies on non-covalent coordination chemistry in an in situ manner, and this supramolecular approach is relatively simple and flexible. It can be applied to not only the labeling of various receptors but also real-time imaging of ligand-induced dynamics of endogenously expressed receptors in live cells.