In the aggregate state, the SOC (T2, S1) and SOC (T3, S1) remain almost unchanged (Fig. ), with a kRISC of ~6.9×10 6 from monomer to aggregate states, that was slightly increased by 1.01 times. Compare with monomer, BTD-FLBr with directed connected bromine atoms in the aggregate state displays obviously larger SOC (T2, S1) and SOC (T3, S1) of 1.30 and 0.86 cm -1 , respectively, leading to dual effective RISC channels (T2 →S1 and T3→S1). Therefore, the kRISC increases by 1.49 folds, reaching 6.70 × 10 7 s -1 due to the more spatial interactions between bromine atoms and π-electrons (Supplementary Fig. ). For BTD-HeBr, the SOC (T2, S1) was dramatically increased from 0.045 to 1.87 cm -1 , and the SOC (T3, S1) also surges from 0.53 to 0.95 cm -1 in the aggerate state. This results in a significant ~73-fold increase in RISC rate (kRISC=2.63 × 10 8 s -1 ) with dual efficient RISC channels. These results indicate that aggregation greatly promotes the RISC process through external heavy atom effects by introducing through-space bromine atoms (Supplementary Fig. ), enables BTD-HeBr to exhibit excellent X-ray scintillation performance.