Chirality is important in the development of pharmaceuticals because more than half of drugs marketed worldwide are chiral. Enantiomers of chiral drugs often differ considerably in their pharmacological and toxicological effects. Thus, the FDA requires that enantiomers be separated when racemic mixtures are produced during synthesis. Crystallization has been used as a means to separate enantiomers in some cases. For example, enantiomers in racemic mixtures crystallize from solution either separately by forming equal amounts of enantiomeric crystals, referred to as conglomerates, or together by forming racemic crystals. Unfortunately, crystallization usually favors formation of racemic crystals (90-95%) over conglomerates (5-10%) because molecules generally pack more efficiently in racemic crystals. We aim to develop surface-based methods that promote formation of conglomerates over racemic crystals as a means to separate enantiomers. Toward this goal, we have investigated crystallization of pharmaceuticals on molecular thin films of achiral and chiral organic molecules that exhibit varying degrees of hydrophobicity/hydrophilicity. The different films were designed to serve as templates that bias homochiral molecular aggregation at the surface, thus favoring nucleation of conglomerates over racemic crystals. Compounds investigated include nimodipine, ibuprofen, sodium ibuprofen, and sodium ammonium tartrate. We demonstrate that the surface and the choice of solvent both play a significant role in controlling the formation of conglomerates versus racemic crystals.