Very recently, Dai et al. designed and synthesized two novel peptidomimetic SARS‐CoV‐2 Mpro inhibitors 61 and 62 (Figure 18) which exhibited extremely high inhibitory activity on purified Mpro with IC50 values of 50 and 40 nM, respectively. Furthermore, the group observed high antiviral activity of both compounds in cell‐based assays (61: EC50, 0.42 µM; 62: EC50, 0.33 µM). X‐ray structures were determined for both derivatives in complex with SARS‐CoV‐2 Mpro at 1.5 Å, providing detailed information about the binding pockets. Similar to related molecules that employ the aldehyde moiety as a warhead, a covalent bond with the active‐site Cys145 was demonstrated for both structures. Cytotoxicity assays revealed CC50 values greater than 100 µM. 155