Facile successive insertion of carbon monoxide and strained alkenes has been observed for both neutral Pd(R)X(Ar-BIAN) and cationic [Pd(R)(MeCN)(Ar-BIAN)]SO3CF3 complexes, i.e., complexes containing the rigid bidentate nitrogen ligands bis(arylimino)acenaphthene (Ar-BIAN; Ar = p-MeOC(6)H(4) (p-An), p-MeC(6)H(4) (p-Tol), o,o’-i-Pr2C6H3), leading to the formation of new multiple insertion products of the type Pd{CH(R’)CH(R’)C(O)CH(R’)CH(R’)C(O)R}X(Ar-BIAN). It appears that the rigidly chelating Ar-BIAN ligands have an activating effect on the insertion of CO and alkenes in palladium-carbon bonds as compared to other (bidentate) phosphorus and nitrogen ligands and a stabilizing effect on the Pd-acyl and Pd-alkyl complexes formed. Insertion of carbon monoxide was completed within 1 min (R = Me, X = Cl, I; R = PhCH(2), X = Br; R = p-MeC(6)H(4), X = I), except in the case of RX = p-NO2C6H4CH2Br, where insertion required 4 h to go to completion. Insertion of norbornadiene, norbornene, and dicyclopentadiene in the cationic acyl complexes [Pd(C(O)Me)(MeCN)(Ar-BIAN)]SO3CF3 occurred instantaneously. Reaction of norbornadiene with the neutral acyl complexes Pd(C(O)Me)Cl(Ar-BIAN) resulted in rapid quantitative insertion, whereas in the case of norbornene and dicyclopentadiene longer reaction times were needed and mixtures of the starting materials and the insertion products were formed. All complexes isolated after alkene insertion have a similar structure, arising from cis addition of PdC(O)R to the exo face of the alkene, with the acyl oxygen atom coordinating to the palladium and the chloride or trifluoromethanesulfonate present as anion. After insertion of norbornadiene in the neutral acyl palladium complex, the resulting alkylpalladium compound [Pd(C7H8C(O)Me)(p-An-BIAN)] Cl reacted further with carbon monoxide to give the isolable complex Pd(C(O)C7H8C(O)Me)Cl(p-An-BIAN) (13a), whereas the analogous trifluoromethanesulfonate complex did not show any reaction with carbon monoxide. The acyl complexes 13a reacted again with norbornadiene to yield quantitatively [Pd(C7H8C(O)C7H8C(O)Me) (p-An-BIAN)] Cl (14a), which reacted with AgSO3CF3 to give [Pd(C7H8C(O)C7H8C(O)Me)(p-An-BIAN)]SO3CF3 (15a). These new complexes 13-15a, formed by stepwise successive insertion reactions of carbon monoxide and alkenes, have been isolated and were fully characterized for the first time and constitute a living oligomer system that may insert further molecules of CO and norbornadiene.