The resonance-enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectra of the organometallic radicals MgCH3 and ZnCH3 are reported. The radicals were generated in a pulsed supersonic expansion and therefore had vibrational and rotational.temperatures of ca. 10 K. The REMPI experiments have resolved the spin-orbit and vibrational structure of the excited state, which is used as an intermediate state in the ZEKE experiment. Because of the intrinsically high resolution of the ZEKE technique, the photoelectron spectra of these radicals were vibrationally resolved. We also report density functional calculations of the geometries and vibrational frequencies of these radicals, and those of the closely related radicals CaCH3 and CdCH3. We have shown how the photoelectron spectra of these radicals can be used to generate high-resolution "experimental" MO diagrams of molecules that contain these fragments. We illustrate this approach with the MO diagram of Zn(CH3)(2).