Macromolecular crystallography and binding essays. Using non-saturating conditions, namely 1:1 and 1:2 ligand/monomer stoichiometries (LMS), we solved 4 new MX structures to be added to the ~500 already deposited Mpro/ligand complex structures, which were possibly all determined in excess of ligand and almost in their entirety exhibiting double occupancy of the ligand. The first ligand is benzyl