Giant Fully Fused Tetrapodal Rylenimides: Design, Synthesis and Optoelectrochemical Characterization via Alkyl Chain and Core Engineering Strategies

In this work, we report the synthesis and comprehensive characterization of a new series of fully fused three-dimensional rylenimide-based derivatives featuring extended π-conjugation through core-fusion strategies and tailored side-chain engineering at the imide nitrogen, resulting in molecular architectures with up to 19 fused rings. The effects of π-extension and alkyl/aryl imide substituents on the optical and electrochemical behavior were systematically studied using UV-vis spectroscopy, cyclic voltammetry, and density functional theory calculations. The results demonstrate that combining π-extension with bulky solubilizing groups effectively suppresses undesired π-π interactions, enhances electronic delocalization, and improves device-relevant properties. This molecular design strategy offers a promising platform for the development of next-generation functional n-type organic semiconductors.