Author Institution: Department of General and Inorganic Chemistry, E\""{o}tv\""{o}s UniversityHeI photoelectron spectra of some alkyl-lithium tetrameric and hexameric clusters have been recorded. In the low energy region (ca. 6.0-9.0 eV) bands have been assigned to ionization from the Li-C cluster orbitals. Ionization from the triply and doubly degenerate orbitals of the tetramers (Td symmetry) and hexamers (D3d symmetry), respectively, causes Jahn-Teller (JT) distortion of the clusters. Ab initio quantum chemical calculations have been performed to understand the nature and extent of the JT distortions