Here, we propose a multiscale modeling framework that couples QM surface-hopping MD, used to model the photoisomerization step, with classical MD, used to model the THI step (Fig ). The accuracy of our classical MD simulations is supported by optimization of selected force field parameters to fit QM energies and gradients for these specific compounds. The rotation mechanism is elucidated by full rotation trajectories (orange arrows in Fig 3 ) and Markov state models that provide conformations and interconversion kinetics of the metastable substates. We also assess motor performance by using weighted ensemble simulations to compute the THI rate constant, and umbrella sampling to compute the free energy drop going from the metastable form to the stable form. Encouragingly, the THI rate constants computed agree well with experimental measurements. The results thus may benefit future design of similar molecular motors.