Unprecedented Growth of 2D Nanostructures in Photo‐Active System Enabled by Secondary Nucleation

Abstract Living polymerization offers an intriguing process to control the nanostructure's explicit size and shape of organic materials. Owing to their thermodynamic stability, organic sensitized materials are intricate to attain precise structures. Herein, the imidazole tethered triphenylamine and their terminals functionalized with amide and dodecyl chain (ITAAL) are reported to facilitate the thermodynamic stable 1D nanostructures and transform to 2D nanosheets upon light stimulation, an unprecedented phenomenon in the realm of triarylamines. Subsequently, kinetically controlled experiments reveal the transverse growth of bundled nanorods from ITAAL, while ITAAL^•+ discloses the lateral growth of extended 2D nanosheets via homo‐seeding living polymerization, resulting in high electrical conductivity. Interestingly, seed ITAAL with a monomer of ITAAL^•+ and perylene diimide leads to extended 1D and 2D nanostructures supporting hetero‐seeding polymerization, which paves the way to investigate the donor–acceptor derived heterostructures with controlled dynamics to promote the design of efficient photovoltaic devices.