In this thesis, a six-membered N,C-palladacycle bearing the 2-phenylaniline bidentate ligand ( A ) [Pd{( C , N )(2?-NH2C6H4)C6H4}(µ-Cl)]2 ha ee repared. Thi alladacycle i readily accessible, insensitive to air, moisture and heat, and suitable for long-term storage. A was found to be capable homogeneous and heterogeneous catalyst for a variety of substrates to afford the coupled products in good to excellent yields. In the first section of the project, we examined A as a homogenous catalyst in the Suzuki and the Heck cross-coupling reactions. Arylbromides such as romobenzene, 2-bromobenzaldehyde, 4-bromoanisole reacted with phenylboronic acids in the Suzuki reaction, and also reacted with styrene methyl acrylate in the Heck reactions. Iodobenzene undergoes the Heck reaction (with good yields) i the presence of the promoter additive FeCl3. In the second section, we utilized A to prepare palladium nanoparticles supported on PEG (poly ethylene glycol). The advantages of this system lie not only in its easy separation from the products, recycling and preventing the loss of metal, it has also excellent chemical and thermal stability, good accessibility and the dispersion of catalytic sites. X-ray diffraction (XRD) technique and transmission electron microscopy (TEM) image showed that palladium dispersed through the support in nanometer size (2-12 nm). This catalytic system exhibited excellent activity in cross-coupling reactions of aryl iodides, bromides and also chlorides in Heck reaction in good yields.