A series of allyl complexes of the general formula [Cp'Mo(η3-C3H5)(CO)2], where Cp'= Cp, CpMe, Cp*, Ind, IndMe, IndMe2, Flu, and three tungsten analogues, has been prepared and characterized by 1H, 13C, and 95Mo NMR, cyclic voltammetry, and the structure of [IndMo(η3-C3H5)(CO)2] was determined by X-ray single crystal analysis. Two conformers, corresponding to the two extreme orientations of the allyl ligand (endo and exo), have been identified in solution by 1H and 95Mo NMR for all the complexes, except for [FluMo(η3-C3H5)(CO)2], which only presents an exo conformation in solution.