The titanium tert-butyl imido compounds [Ti(NBu ^t )Cl ₂ (NC ₅ H ₄ R-4) _n ] (R = H, n = 2 or 3; R = Bu ^t , n = 2) have been found to be entry points to the half-sandwich η ⁵ -cyclopentadienyl derivatives [Ti(η ⁵ -C ₅ R′ ₄ R″)(NBu ^t )Cl(NC ₅ H ₄ R-4)] (R = Bu ^t , R′ = R″ = H or Me; R = H, R′ = H, R″ = H, Me or Pr ⁱ ; R = H, R′ = Me, R″ = Me, Et or C ₄ H ₇ ), the η ⁵ -1,2,3-trimethylindenyl species [Ti(η ⁵ -C ₉ H ₄ Me ₃ )(NBu ^t )Cl(NC ₅ H ₄ Bu ^t -4)] and the bis(η ⁵ -cyclopentadienyl) compound [Ti(η ⁵ -C ₅ H ₅ ) ₂ (NBu ^t )(NC ₅ H ₅ )], the crystal structure of which has been determined. The complex [Ti(η ⁵ -C ₅ H ₅ )(NBu ^t )Cl(NC ₅ H ₅ )] readily loses pyridine under vacuum in the solid state to form the binuclear complex [Ti ₂ (η ⁵ -C ₅ H ₅ ) ₂ ( µ-NBu ^t ) ₂ Cl ₂ ]. Treatment of [Ti(η ⁵ -C ₅ Me ₄ R)(NBu ^t )Cl(NC ₅ H ₅ )] (R = Me or Et) with Na[C ₅ H ₅ ] gives the corresponding mixed-ring sandwich derivatives [Ti(η ⁵ -C ₅ H ₅ )(η ⁵ -C ₅ Me ₄ R)(NBu ^t )Cl(NC ₅ H ₅ )]. Addition of Li[C ₉ H ₇ ] to [Ti(η ⁵ -C ₅ H ₅ )(NBu ^t )Cl(NC ₅ H ₅ )] gave the η ⁵ -cyclopentadienyl, η ³ -indenyl mixed-ring analogue [Ti(η ⁵ -C ₅ H ₅ )(η ³ -C ₉ H ₇ )(NBu ^t )(NC ₅ H ₅ )]. The complex [Ti(η ⁵ -C ₅ H ₅ ) ₂ (NBu ^t )(NC ₅ H ₅ )] undergoes a room-temperature cyclopentadienyl ligand-redistribution reaction with [Ti(NBu ^t )Cl ₂ (NC ₅ H ₅ ) ₂ ] forming [Ti(η ⁵ -C ₅ H ₅ )(NBu ^t )Cl(NC ₅ H ₅ )] in quantitative yield. Variable-temperature NMR spectra for the half-sandwich complexes show that the co-ordinated pyridine exchanges with free pyridine via an associative mechanism. The compound [Ti(η ⁵ -C ₅ H ₅ )(η ⁵ -C ₅ Me ₄ Et)(NBu ^t )(NC ₅ H ₅ )] is also fluxional and exhibits reversible pyridine dissociation at higher temperatures and restricted rotation about the Ti–N (pyridine) bond at lower temperatures.