This supplementary material provides a detailed description of the electron spin polarization model and the coupled stochastic-Liouville equations used to describe the dynamics of multiexcitons in a metal-organic framework (MOF). The model considers the molecular motions and exciton migrations in the TT and T+T states, focusing on the quintet-triplet-singlet (Q-T-S) mixing. The equations describe the time evolution of the density matrices for the strongly coupled TT1 state, the thermally activated TT2 state, and the decoupled T+T state. The model incorporates spin Hamiltonians, exchange rate constants, and recombination rates, and accounts for the effects of the external magnetic field on the spin states. The equations are used to calculate the TREPR spectra and the EPR line shape for the T1S0 pair state generated by triplet-triplet annihilation. The model also includes the computation of the transverse magnetization in pulsed EPR measurements, considering the nutation profiles and echo-detected field swept spectra. The supplementary materials include figures and tables that provide additional information on the experimental setup, the computational parameters, and the results of the simulations. The study demonstrates the room-temperature quantum coherence of entangled multiexcitons in a MOF, highlighting the potential for quantum information processing and spin-based applications.This supplementary material provides a detailed description of the electron spin polarization model and the coupled stochastic-Liouville equations used to describe the dynamics of multiexcitons in a metal-organic framework (MOF). The model considers the molecular motions and exciton migrations in the TT and T+T states, focusing on the quintet-triplet-singlet (Q-T-S) mixing. The equations describe the time evolution of the density matrices for the strongly coupled TT1 state, the thermally activated TT2 state, and the decoupled T+T state. The model incorporates spin Hamiltonians, exchange rate constants, and recombination rates, and accounts for the effects of the external magnetic field on the spin states. The equations are used to calculate the TREPR spectra and the EPR line shape for the T1S0 pair state generated by triplet-triplet annihilation. The model also includes the computation of the transverse magnetization in pulsed EPR measurements, considering the nutation profiles and echo-detected field swept spectra. The supplementary materials include figures and tables that provide additional information on the experimental setup, the computational parameters, and the results of the simulations. The study demonstrates the room-temperature quantum coherence of entangled multiexcitons in a MOF, highlighting the potential for quantum information processing and spin-based applications.