The synthesis of chiral metal-organic frameworks (MOFs)i sh ighly relevant for asymmetric heterogenous catalysis, yet very challenging. Chiral MOFsw ith MOF-74 topology were synthesised by using post-synthetic modification with proline. Vibrational circular dichroism studies demonstrate that prolinei st he source of chirality.T he solvents used in the synthesis play ak ey role in tuning the loading of proline and its interaction with the MOF-74 framework. In N,N'-dimethylformamide, proline coordinates monodentate to the Zn 2 + ions withint he MOF-74 framework, whereasi ti s only weakly bound to the frameworkw hen using methanol as solvent. Introducing chirality within the MOF-74f ramework also leads to the formation of defects, with both the organic linkera nd metal ions missing from the framework. The formationo fd efects combined with the coordination of DMF and prolinew ithin the framework leads to ap ore blockinge ffect. This is confirmed by adsorption studies and testingo ft he chiral MOFs in the asymmetric aldol reaction betweenacetone and para-nitrobenzaldehyde.