Preparation of organic semiconductors by solution processes is desirable to create flexible electronic devices. The use of soluble precursors, which exhibit high solubility in common organic solvents and afford the corresponding semiconducting molecules upon appropriate external stimuli such as heat and light, is a promising approach to realize this goal. Our group recently reported new soluble precursors, namely dinaphtho[1,8‐bc:1′,8′‐ef]thiepine bisimide (DNTBI) and its sulfoxide, which afforded perylene bisimide, a representative n‐type organic semiconductor, upon heating or light‐irradiation. In this work, we report the second‐generation synthetic route to DNTBI, which enabled gram‐scale and diversity‐oriented preparation of various N‐substituted DNTBIs. We also disclosed the suitable combination of leaving group (S or SO), external stimulus (heat or light), and N‐substituent to realize efficient charge transport.