The catalytic system RhCl3⋅3H2O/2P(p-CH3C6H4)3/65nBu4PI/2I2, which was discovered recently in our research group, allows the highest catalytic activity ever reported for the intermolecular hydroamination of ethylene, 1-butene, and 1-hexene with aniline-type amines (0.3 mol % catalytic precursor) to give the expected N-alkyl- (N-ethyl-, 1) and N,N-dialkyl-anilines (N,N-diethyl-, 2) along with 2-methyl quinolines (3; in the case of ethylene). The effects of time and temperature, as well as the nature of the phosphonium salt, phosphine, and amine on the catalytic activity of this reaction have been studied. This system is particularly efficient for the hydroamination of ethylene with aniline in the presence of 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (CE*=460) and tri(p-tolyl)phosphine (CE*=520). Good to excellent activities were also found by combining Wilkinson’s catalysts (RhI complexes) with nBu4PI and I2. The simple association of PPh3 and I2 has been shown to be a very efficient “in-situ generated” source of I− promoters. *CE (catalytic efficiency)=TON1+2TON2+2TON3.