A new stepwise preparation of tungstenocene derivatives [Cp 2 WL 2 ][BF 4 ] 2 (L=CO or NCMe) from [W(CO) 6 ] via [CpW(η 3 -C 3 -H 5 )(CO) 2 ] and [CpW(η 4 -C 5 H 6 )(CO) 2 ]BF 4 is described. Similar preparations, starting from [(η 5 -C 9 H 7 )W(η 3 -C 9 H 7 )(CO) 2 ], lead to the first mixed-ring indenyl analogues of tungstenocene, [IndCpWL 2 ][BF 4 ] 2 (L = CO or NCMe) and [CpW(η 3 -Ind)(CO) 2 ]. Reversible ring slippage between [(η 5 -C 9 H 7 )W(CO) 2 (NCMe) 2 ]BF 4 and [(η 3 -C 9 H 7 )W(CO) 2 (NCMe) 3 ]BF 4 is observed.