These results contrast a closely related system reported by our group in which sequential metalation and ring-opening and dearomatisation of furans is observed. Experiments directly support the DFT predictions and a series of aluminated thiophene and benzothiophene analogues have been isolated and structurally characterised. No evidence for ring-opening was found experimentally. The difference in reactivity between thiophenes and furans is explained through the stabilisation of a key intermediate Supporting Information.