Abstract Starting from asymmetric Thiele's acid derivatives, two different imaging probes [99m Tc (CO) 3 (CpR)](R= potential targeting vector) are generated simultaneously in one- pot and from one substrate. This extends the previously introduced labeling strategy of metal- mediated retro-Diels [BOND] Alder reaction with HCp-R dimers. We demonstrate that chemically active functionalities such as hydroxamic acids are not following this labeling ...