The aprotic and protic bi- and multidentate iminophosphines 2-Ph 2PC 6H 4NCR 1R 2 (R 1=H, R 2=Ph= 2a; R 1=Me R 2=Ph= 2b; R 1=H, R 2=2-thienyl= 2c; R 1=H, R 2=C 6H 4-2-PPh 2= 2d; R 1=H, R 2=C 6H 4-2-OH= 2e, R 1=H, R 2=C 6H 4-2-OH-3-Bu t = 2f; R 1=H, R 2=CH 2C(O)Me= 2g) have been prepared by the acid catalyzed condensation of 2-(diphenylphosphino)aniline with the corresponding aldehyde–ketone. Iminophosphine 2d can be reduced with sodium cyanoborohydride to give the corresponding amino-diphosphine 2-Ph 2PC 6H 4N(H)CH 2C 6H 4-2-PPh 2 ( 2h). In the presence of a stoichiometric quantity of acid, 2-(diphenylphosphino)aniline reacts in an unexpected manner with benzaldehyde, salicylaldehyde, or acetophenone to give the corresponding 2,3-dihydro-1 H-benzo[1,3]azaphosphol-3-ium salts and with pyridine-2-carboxaldehyde to give N-(pyridin-2-ylmethyl)-2-diphenylphosphinoylaniline, the latter of which has been characterized by single-crystal X-ray crystallography, as its palladium dichloride derivative. The attempted condensation of 2-(diphenylphosphino)aniline with pyridine-2-carboxaldehyde to give the corresponding pyridine-functionalized iminophosphine resulted in an unusual transformation involving the diastereoselective addition of two equivalents of aldehyde to give 1,2-dipyridin-2-yl-2-( o-diphenylphosphinoyl)phenylamino-ethanol, which has been characterized by a single-crystal X-ray structure determination. The bidentate iminophosphine 2-Ph 2PC 6H 4NC(H)Ph reacts with [(cycloocta-1,5-diene)PdClX] X=Cl, Me) to give [Pd{2-Ph 2PC 6H 4NC(H)Ph}ClX] and the imino-diphosphine 2-Ph 2PC 6H 4NC(H)C 6H 4-PPh 2 reacts with [(cycloocta-1,5-diene)PdClMe] to give [Pd{2-Ph 2PC 6H 4NC(H)C 6H 4PPh 2}ClMe] and each has been characterized by single-crystal X-ray crystallography. The monobasic iminophosphine 2-Ph 2PC 6H 4NC(Me)CH 2C(O)Me reacts with [Ni(PPh 3) 2Cl 2] in the presence of NaH to give the phosphino–ketoiminate complex [Ni{2-Ph 2PC 6H 4NC(Me)CHC(O)Me}Cl], which has been structurally characterized. Mixtures of iminophosphines 2a– h and a palladium source catalyze the Suzuki cross coupling of 4-bromoacetophenone with phenyl boronic acid. The efficiency of these catalysts show a marked dependence on the palladium source, catalysts formed from [Pd 2(OAc) 6] giving consistently higher conversions than those formed from [Pd 2(dba) 3] and [PdCl 2(MeCN) 2]. Catalysts formed from neutral bi- and terdentate iminophosphines 2a– d gave significantly higher conversions than those formed from their monobasic counterparts 2e– f. Notably, under our conditions the conversions obtained with 2a– c compare favorably with those of the standards; catalysts formed from tris(2-tolyl)phosphine and tris(2,4-di- tert-butylphenyl)phosphite and a source of palladium. In addition, mixtures of [Ir(COD)Cl] 2 and 2a– h are active for the hydrosilylation of acetophenone; in this case catalysts formed from monobasic iminophosphines 2e– f giving the highest conversions.