In this presentation, we present a core-shell drop-drying (CSDD) method that employs spontaneous formation of the core-shell droplet for the efficient growth of organic molecular crystals. A drop-drying method is one of the simplest crystallization methods that allows a direct growth of organic molecular crystals on a solid substrate. Despite the advantages of drop-drying process, the practical applications to organic molecular crystals are very limited due to the poor area-selectivity and low crystallinity of the resulting crystals. To overcome these limitations, a modified drop-drying method that employs a droplet-in-droplet system is newly designed. The droplet-in-droplet system has an inner core that droplet enables area selective growth with suppressed coffee-ring effect, and an outer shell droplet that provides enough crystallization time to form well-defined facets. Using this concept, well-defined ribbon-shaped methylene blue crystals were successfully grown from methanol/mestiylene core-shell droplets with significantly diminished coffee-ring effect, while the conventional mono-solvent system using methanol solution did not succeed. The crystallization mechanism of CSDD revealed that the diffusion and evaporation of solvents at the core-shell and shell-air interfaces were key factors for suppressing coffee-ring effect. In addition, the CSDD method provides the diversity of crystal in terms of sizes and growth direction by changing the droplet condition, such as concentration or solvent volume ratio. We expect that this method will not only contribute the in-depth understanding of crystallization mechanism in binary solvent systems but also expand the usage of drop-drying method to develop organic molecular crystals that could be applied in various fields.