Organic light-emitting diodes (OLEDs) have gained significant attention in recent years due to their high efficiency, low power consumption, and thin form factor, etc. Among them, molecules showing TADF phenomenon called 3rd generation OLED are received particular attention because of its theoretical potential achieving 100% IQE. Although this material has many advantages, such as no precious metals, high efficiency, and low voltage operation, there are many things that need to be improved for practical use. In this study, Optimal candidate TADF molecule for OLED was selected by applying Reinforcement learning which has role of strategy for combinational chemistry. In process for this goal, we computationally investigate the candidate molecules by connecting each fragment to make TADF polymer structure, and some of that seem to be optimal structure.