Tricarbonyl(1,2,3,4,5-pentamethyl)chromium(0) (I) is obtained from pentamethylpyrrole and tetracarbonyl(norbornadiene)chromium(0) in good yield. The mol. geometry of I calcd. from x-ray data indicates pentamethylpyrrole to be a stronger donor ligand on comparison with N-methylpyrrole in tricarbonyl(N-methylpyrrole)chromium(0). This result is confirmed by an AM1 calcn. of N-methylpyrrole and pentamethylpyrrole.