Singlet fission (SF) is a spin-allowed process in which a singlet exciton, (1)(S1S0), within an assembly of two or more chromophores spontaneously down-converts into two triplet excitons via a multiexciton correlated triplet pair state, (1)(T1T1). To elucidate the involvement of charge transfer (CT) states and vibronic coupling in SF, we performed 2D electronic spectroscopy (2DES) on dilute solutions of a covalently linked, slip-stacked terrylene-3,4:11,12-bis-(dicarboximide) (TDI) dimer. This dimer undergoes efficient SF in nonpolar 1,4-dioxane and symmetry-breaking charge separation in polar dichloromethane. The various 2DES spectral features in 1,4-dioxane show different pump wave-length dependencies, supporting the presence of mixed states with variable (1)(S1S0), (1)(T1T1) and CT contributions that evolve with time. Analysis of the 2DES spectra in dichloromethane reveals the presence of a state having largely (1)(T1T1) character during charge separation. Therefore, the (1)(T1T1) multiexciton state plays an important role in the photophysics of this TDI dimer irrespective of solvent polarity.