Classical chemical dynamics simulations, were performed to study the intramolecular and unimolecular dissociation dynamics of the benzene dimer, Bz(2) -> Bz. The dissociation of microcanonical ensembles of Bz(2) vibrational states, at energies E corresponding to temperatures T of 700-1500 K, were simulated. For the large Bz(2) energies and large number of Bz(2) vibrational degrees of freedom, s, the classical microcanonical (RRKM) and canonical (TST) rate Constant expressions become identical. The dissociation rate constant for each T is determined from the initial rate dN(t)/dt of Bz(2) dissociation, and the k(T) are well-represented by the Arrhenius eq-k(T) = A -exp(-E-a/RT). The E-a of 2.02 kcal/mol agrees well with the Bz(2) disseciation energy 2.32 kcal/mol, and the A,factor of 2.43 X 10(12) s(-1) is of the expected order-Of-magnitude. The form of N(t) is nonexponential, resulting from weak coupling, between the Bz(2) intramolecular and intermolecular nodes. With this weak coupling, large Bz(2) vibrational excitation, and low Bz(2) dissociation energy, most of the trajectories dissociate directly. Simulations, with only the Bz(2) intramolecular modes excited at 1000 K, were also performed to study intramolecular Vibrational energy redistribution,(IVR) between. the intramolecular and intermolecular modes. Because of restricted IVR, the initial dissociation is quite slow, but N(t) ultimately becomes exponential, suggesting an IVR time of 20.7 ps.