Developing efficient giant oligomeric donors to replace batch-varied polymers in organic solar cells (OSCs) is challenging. This study designs two isomeric rhodanine-based linkers to regulate the assembly of giant dimeric donors (G-Dimer-Ds). Pairing these with the giant dimeric acceptor DY creates all-giant-oligomer OSCs (AGO-OSCs) achieving over 16% efficiency and superior photostability (extrapolated *T*₈₀ of ~10,000 hours). G-Dimer-D2, with its lower homo-molecular interaction and stronger thermal-driven assembly, reduces energetic disorder, improves charge transport, and provides stable morphology. This work provides design principles for efficient giant donors and a promising type of OSC with defined structures, high efficiency, and excellent stability.

Caixuan Wang, Xiaoming Ma, Dan Deng, Hao Zhang, Rui Sun, Jianqi Zhang, Lili Zhang, Mengying Wu, Jie Min, Zhi-Guo Zhang, Zhixiang Wei