Ferrocene End‐Capped Porphyrin Donor for Dual Regulation of Molecular Ordering and Donor/Acceptor Miscibility in All‐Small‐Molecule Organic Solar Cells

All‐small‐molecule organic solar cells (ASM‐OSCs) are promising for commercialization owing to their defined molecular structures and high reproducibility. However, achieving simultaneously optimized molecular ordering and favorable donor/acceptor (D/A) miscibility in the active layer remains a critical bottleneck limiting their efficiency. Herein, we designed a ferrocene‐end‐capped porphyrin donor, ZnP‐Fc, via terminal‐group engineering of ZnP‐TEH. The introduced electron‐rich ferrocene unit promotes interaction‐driven ordering and optimizes D/A compatibility, thereby forming compact π‐π stacking that is conducive to fast charge extraction. Consequently, ZnP‐Fc:6TIC binary device achieves a PCE of 15.44%, surpassing that of ZnP‐TEH‐based devices with higher J SC and FF. Furthermore, ternary devices based on ZnP‐Fc:ZnP‐TEH:6TIC leverage a donor‐alloy configuration to reconcile compatibility with ordered packing, delivering a PCE of 16.52%. Taken together, this work highlights end‐group engineering as an effective lever to manipulate molecular ordering and D/A compatibility, providing actionable guidelines for developing high‐performance ASM‐OSCs.