The reactions of acrylonitrile (AN) with "L2PdMe+" species were investigated; (L-2 = CH2(N-Me-imidazol-2-yl)(2) (a, bim), (p-tolyl)(3)CCH(N-Me-imidazol-2-yl)(2) (b, Tbim), CH2(5-Me-2-pyridyl)2 (c, CH(2)py'(2)), 4,4'-Me-2-2,2'-bipyridine (d), 4,4'-Bu-t(2)-2,2'-bipyridine (e), (2,6-Pr-i(2)-C6H3)N CMeCMe=N(2,6-Pr-i(2)-C6H3) (f)). [L2PdMe(NMe2Ph)][B(C6F5)(4)](2a-c) and [{L2PdMe}(2)(u-Cl)][B(C6F5)(4)](2d-f) react with AN to form N-bound adducts L2Pd(Me)(NCCH=CH2)(+) (3a-f). 3a-e undergo 2,1 insertion to yield L2Pd{CH(CN)Et}(+), which form aggregates [L2Pd{CH(CN)Et}](n)(n+) (n = 1-3, 4a-e) in which the Pd units are proposed to be linked by PdCHEtCN --- Pd bridges. 3f does not insert AN at 23 degreesC. 4a-e were characterized by NMR, ESI-MS, IR and derivatization to L2Pd{CH(CN)Et}(PR3)(+) (R = Ph (5a-e), Me (6a-c)). 4a,b react with CO to form L2Pd{CH(CN)Et}(CO)(+) (7a,b). 7a reacts with CO by slow reversible insertion to yield (bim)Pd{C(=O)CH-(CN)Et}(CO)(+) (8a). 4a-e do not react with ethylene. (Tbim)PdMe+ coordinates AN more weakly than ethylene, and AN insertion of 3b is slower than ethylene insertion of (Tbim)Pd(Me)(CH2=CH2)(+) (10b). These results show that most important obstacles to insertion polymerization or copolymerization of AN using L2PdR+ catalysts are the tendency of L2Pd{CH(CN)CH2R}(+) species to aggregate, which competes with monomer coordination, and the low insertion reactivity of L2Pd{CH(CN)CH2R}(substrate)(+) species.