The phosphinimide complexes (t-Bu 3 PN)TiCl 3 (1) and (t-Bu 3 PN) 2 TiCl 2 (4) are readily prepared in high yields from the stoichiometric reaction of t-Bu 3 PNSiMe 3 and TiCl 4 , while (t-Bu 3 PN) 3 TiCl ( 11) is readily obtained from the reaction of t-Bu 3 PNLi and TiCl 4 . The analogous 1:1 or 2:1 reactions of ZrCl 4 and t-Bu 3 PNLi afford mixtures of products, although in the 3:1 stoichiometric ratio (t-Bu 3 PN) 3 ZrCl ( 12) is isolable. These complexes are readily alkylated with a variety of reagents to give (t-Bu 3 PN)TiMe 3 (2), (t-Bu 3 PN)Ti(CH 2 Ph) 3 ( 3), (t-Bu 3 PN) 2 TiMe 2 ( 5), (t-Bu 3 PN) 2 Ti(η 3 -C 3 H 5 ) 2 ( 6), (t-Bu 3 PN) 2 Ti(CH 2 Ph) 2 ( 7), (t-Bu 3 PN) 2 TiPh 2 (8), (t-Bu 3 PN) 2 Ti(η 5 -Cp)Cl ( 9), (t-Bu 3 PN) 2 Ti(η 5 -Cp)Me ( 10), (t-Bu 3 PN) 3 TiMe ( 13), (t-Bu 3 -PN) 3 TiPh ( 14), (t-Bu 3 PN) 3 ZrMe ( 15), (t-Bu 3 PN) 3 Zr(CH 2 Ph) (16), and (t-Bu 3 PN) 3 Zr(η 5 -Cp) ( 17). Subsequent reactions of some of these alkyl derivatives with [PhNMe 2 H][B(C 6 F 5 ) 4 ], [Ph 3 C]-[B(C 6 F 5 ) 4 ], or B(C 6 F 5 ) 3 are investigated. A number of zwitterionic and cationic species complexes have been characterized. These include [(t-Bu 3 PN)Ti(CH 2 Ph) 2 (PhCH 2 )B(C 6 F 5 ) 3 ] (18), [(t-Bu 3 PN) 2 TiMe(PMe 3 )][B(C 6 F 5 ) 4 ] ( 19), (t-Bu 3 PN) 2 TiMe (µ-MeB(C 6 F 5 ) 3 ) ( 20), (t-Bu 3 -PN) 2 Ti(µ-MeB(C 6 F 5 ) 3 ) 2 (21), and (t-Bu 3 PN) 2 Ti(C 6 F 5 ) 2 ( 22). The implications of this chemistry are considered. Structural data for 1, 4, 5, 12, 16, 21, and 22 are described.