A small molecule organic semiconductor CuTBP (copper tetrabenzoporphyrin) was formed from a precursor CuCP (Copper tetrabicycloporphyrin) using a solution process. In this study, the solid-state crystallization process of CuTBP on a substrate surface was observed and evaluated. To obtain good semiconductor performance, it is very important to understand and control the crystallization process, which was found to consist of three steps during annealing. These steps were clearly observed with XRD-DSC. Although the starting temperatures of the first and second CuTBP crystallization steps did not show distinct changes, the starting temperature of the third step changed significantly with the heating rate, requiring a temperature higher than 145 degrees C. The grain morphology also changed depending on the crystallization temperature. At lower crystallization temperatures, the growth of homogeneously colored grains having diamond shapes was promoted, while at higher temperatures heterogeneously colored grains of petal shapes were formed.