The reactivity of (η3-allyl)palladium chloro dimers [(1-R-η3-C3H4)PdCl]2 (R = H or Me) towards a sterically hindered diphosphazane ligand [EtN{P(OR) 2}2] (R = C6H3(Pri) 2-2,6), has been investigated under different reaction conditions. When the reaction is carried out using NH4PF6 as the halide scavenger, the cationic complex [(1-R-η3-C 3H4)Pd{EtN(P(OR)2)2}]PF6 (R = H or Me) is formed as the sole product. In the absence of NH 4PF6, the initially formed cationic complex, [(η3-C3H5)Pd{EtN(P(OR)2) 2}]Cl, is transformed into a mixture of chloro bridged complexes over a period of 4 days. The dinuclear complexes, [(η3-C 3H5)Pd2(-Cl)2{P(O)(OR) 2}{P(OR)2(NHEt)}] and [Pd(-Cl){P(O)(OR) 2}{P(OR)2(NHEt)}]2 are formed by P-N bond hydrolysis, whereas the octa-palladium complex [(η3-C 3H5)(2-Cl-η3-C3H 4)Pd4(-Cl)4(-EtN{P(OR)2} 2)]2, is formed as a result of nucleophilic substitution by a chloride ligand at the central carbon of an allyl fragment. The reaction of [EtN{P(OR)2}2] with [(η3-C 3H5)PdCl]2 in the presence of K 2CO3 yields a stable dinuclear (η3-allyl) palladium(i) diphosphazane complex, [(η3-C3H 5)[-EtN{P(OR)2}2Pd2Cl] which contains a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and high TON's in the catalytic hydrophenylation of norbornene. © The Royal Society of Chemistry.