Several prochiral NCN pincer complexes of palladium(II) including hemilabile ligands and a long aliphatic chain were synthesized and characterized spectroscopically. In some of the complexes, the presence of two different substituents on the N donor atoms made them stereogenic so that they were isolated as a mixture of diastereoisomers, which could be differentiated by 1 H NMR. Binding of some of these complexes to bovine b-lactoglobin by insertion within its inner cavity was theoretically investigated by molecular docking simulations and experimentally confirmed by CD spectroscopy.Adjunction of H-bond donor substituents on the ligand framework gave more stable supramolecular protein -complex assemblies. These constructs were shown to catalyze aldol condensation reactions in aqueous medium affording in some cases the less favorable cis-product. Since the corresponding complexes gave exclusively the trans product in the absence of b-lactoglobulin, this unusual diastereoselectivity was ensued by the second sphere of coordination brought by the protein host.2