The stable ionic Pd II complexes 1A-4A were synthesized through the complexation of PdCl 2 (MeCN) 2 with the phosphane-functionalized ionic liquids (FILs) 1-4 with π-acceptor character. Single-crystal X-ray diffraction analyses showed that 1A-4A were all composed of Pd II -centred square-planar cations and triflate (OTf -, CF 3 SO 3 -) counteranions. The complex cations in 1A-3A possessed structural similarity to trans-PdCl 2 (PPh 3 ) 2 . The cation in 4A was a new Pd II -centered planar complex ligated by the phosphane-carbon anioncarbene (PCC) pincer in a tripodal manner. The stabilities of 1A-4A were improved due to the intensive π-backbonding interaction between the Pd and P atoms. When complexes 1A-4A were used as precatalysts for homogeneous carbonylative Sonogashira coupling of PhI with phenylacetylene [a] Shanghai Key Scheme 1. Syntheses of the ionic Pd complexes 1A-4A ligated by the phosphane-FILs 1-4. Eur. J. Inorg. Chem. 2014, 975-985