Modular π ‐Extended IF‐TTF Systems: Tuning Redox and Optical Properties in Donor–Acceptor and Donor–Donor Frameworks

A series of π ‐extended donor–acceptor and donor–donor systems incorporating an indeno[1,2‐ b ]fluorene‐extended tetrathiafulvalene (IF‐TTF) donor was synthesized and characterized. Electrochemical studies revealed that the intrinsic redox properties of the parent donor and acceptor fragments are largely retained upon covalent linking. The donor–acceptor compounds exhibit IF‐TTF‐centered oxidations and acceptor‐localized reductions, whereas the donor–donor systems undergo up to four sequential reversible oxidations. UV–vis absorption spectroscopy showed preservation of the characteristic optical features of the individual chromophores, while weak charge‐transfer bands and solvatochromism indicate moderate donor–acceptor interactions. These results demonstrate that covalent coupling of redox‐active building blocks provides a versatile strategy for accessing tunable molecular systems with multiple reversible redox states.