Electron propagator calculations on electron affinities of ZnCH3+ and ionization energies of ZnCH3- provide ZnCH3 excitation energies. Excited states involving promotion of an electron from one Zn-centered hybrid to another, as well as Zn-C bond to Zn-centered hybrid charge-transfer states, are obtained. The lowest excited state, which is of the former type with an unpaired electron in a Zn-centered, p-like hybrid orbital, lies 2.98 eV above the ground state, in close agreement with spectroscopic results. A charge-transfer state, where two electrons reside in a Zn-centered, s-like hybrid orbital and an unpaired electron is described by a Zn-C bond orbital, is 4.48 eV above the ground state. Additional excited states also have been calculated. Vertical ionization energies of ZnCH3-, as well as the vertical ionization energy and several vertical electron affinities of ZnCH3+, have been determined. ZnCH3’s adiabatic ionization energy, 7.06 eV, and adiabatic electron affinity, 0.95 eV, have been inferred from additional calculations. Vertical ionization energies of Zn(CH3)(2) are calculated with similar techniques and are in excellent agreement with photoelectron spectrum results. Bond energies for the dissociation of one or both methyl groups have been determined as well.