• • End-group engineering modulates LUMO electron density at linkage atoms, yielding super-exchange couplings spanning 0.1–10 meV for intramolecular electron transfer, directly impacting charge separation efficiency in OSCs.
• • The new-designed NB-V achieves a 15% increase in light absorption coefficient (λmax = 750 nm, ε > 1.2 × 10^5 cm⁻¹) and a 20% enhancement in electron mobility (μe = 1.5 × 10⁻³ cm² V⁻¹ s⁻¹) compared to BB-V, enabling higher short-circuit current densities.
• • Intermolecular electronic couplings vary by up to 50 meV among DSMAs, with NB-V exhibiting balanced couplings (intramolecular: 8 meV; intermolecular: 12 meV) that reduce recombination losses and improve fill factor.
• • The power conversion efficiency of DSMA-based OSCs is highly sensitive to dimerization modes, with EG-engineered NB-V potentially reaching PCE > 18% (vs. 16.5% for BB-V), addressing the reproducibility challenges of polymerized SMAs.