A simple method to control the nucleation and morphology of (4-N,N-dimethylamino-4-N-methyl-stilbazoliumtosylate) DAST crystals is explored. At equal concentrations of oleic acid and DAST in methanol, pure DAST crystals with an irregular hexagonal shape are obtained by a solvent evaporation method. The influence of oleic acid on facilitating the growth in specific faces is investigated. The purity of the grown crystal is investigated by powder XRD, NMR and Raman spectroscopy analyses. As a major improvement, we present a method where a preference for the growth of one of the desired faces (010) in the final morphology of the DAST crystal is possible which would be attractive for terahertz generation and detection studies.