Cell permeable probes to image the presence and localization of kinases are important in studying their function and as diagnostic tools. Despite the central role of kinases as therapeutic targets, there are remarkably few probes available. Herein we report the discovery of a probe to image two therapeutically relevant kinases: EGFR and ERBB2. The probe was identified from a library based on a scaffold derived from the resorcyclic acid lactones that form a covalent adduct by reacting specifically with an unconserved cysteine in the nucleotide-binding site of the kinases. We demonstrated the utility of the newly discovered probe by imaging of EGFR localization and ERBB2 inhibition in live cells.