Tripodal ligands, 1,1,1-tris(diphenylphosphinomethyl)ethane [CH3C(CH2PPh2)(3)] [P-3] and 1,1,1-tris(diphenylphosphinomethyl)ethane trisulphide [CH3C(CH2P(S)Ph-2)(3)] [P3S3] have been introduced to stabilize Pd-o-nanoparticles having small core diameter and narrow size distribution. The Pd-o-nanoparticles were synthesized by the reduction of K2PdCl4 precursor with NaBH4 in the presence of ligand P-3 or P3S3 using two phases, one pot reaction at room temperature. TEM and XRD studies indicate that P-3 stabilizes smaller sized Pd-o-nanoparticles (<3 nm) compared to that stabilized by P3S3 (<5 nm), which are attributable to the stronger interaction of Pd-o (Soft) with P (Soft) than Pd-o (Soft) with S (less Softer than P). The Pd-o-nanoparticles exhibit face centered cubic (fcc) lattice geometry and high thermal stability (similar to 150 degrees C). The synthesized Pd-o-nanoparticles serve as an efficient catalyst for the carbon-carbon bond formation reactions, e. g. in Suzuki coupling reaction, aryl halides and arylboronic acids result cross-coupling products with about 94% isolated yield and 100% selectivity; in Heck coupling reaction, the vinylation of aryl halides with olefins result coupling products with 97% yield and >99% trans selectivity while in the alkynylation of aryl halides with terminal alkynes, i.e. Sonogashira coupling reaction, the cross-coupling products of about 94% isolated yield with 100% selectivity were observed. The synthesized nanocatalysts could be reused without significant loss of their catalytic activity. (C) 2012 Elsevier B. V. All rights reserved.