The compounds, 2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine ( Me NˆNˆN) (L1) and 2,6-bis(3,5-ditertbutylpyrazol-1-ylmethyl)pyridine ( tBu NˆNˆN) (L2), react with either [Pd(NCMe) 2 Cl 2 ] or [Pd(COD)ClMe] to form the mononuclear palladium complexes [Pd( Me NˆNˆN)Cl 2 ] (1), [Pd( Me NˆNˆN)ClMe] (2), [Pd( tBu NˆNˆN)Cl 2 ] (3) and [Pd( tBu NˆNˆN)ClMe] (4). Reactions of 1, 2 and 4 with the halide abstractor, NaBAr 4 (Ar=3,5-(CF 3 ) 2 C 6 H 3 ), led to the formation of stable tridentate cationic species [Pd( Me NˆNˆN)Cl] + (5), [Pd( Me NˆNˆN)Me] + (6) and [Pd( tBu NˆNˆN)Cl] + (7) respectively. The analogous carbonyl linker cationic species [Pd{(3,5-Me 2 pz-CO) 2 -py}Cl] + (9) and [Pd{(3,5- t Bu 2 pz-CO) 2 -py}Cl] + (10), prepared by halide abstraction of the neutral complexes [Pd{(3,5-Me 2 pz-CO) 2 -py}Cl 2 ] and [Pd{(3,5- t Bu 2 pz-CO) 2 -py}Cl 2 ] by NaBAr 4 , were however less stable with t 1/2 of 14 and 2days respectively. Attempts to crystallize 1 and 3 from the mother liquor resulted in the isolation of the salts [Pd( Me NˆNˆN)Cl] 2 [Pd 2 Cl 6 ] (11) and [Pd( tBu NˆNˆN)Cl] 2 [Pd 2 Cl 6 ] (12). Although when complexes 1–4 were reacted with modified methylaluminoxane (MMAO) or NaBAr 4 , no active catalysts for ethylene oligomerization or polymerization were formed, activation with silver triflate (AgOTf) produced active catalysts that oligomerized and polymerized phenylacetylene to a mixture of cis-transoidal and trans-cisoidal polyphenylacetylene.