In this thesis, two new dendrimers containing metallic nanoparticles of ruthenium and copper were prepared. In project I, a first generation dendrimer was prepared by a divergent reaction of hexakis(bromomehyl)benzene with vanillin in the presence of potassium carbonate. The obtained dendrimer was characterized by FT-IR and 1 H-NMR. A second generation dendrimer was then prepared by a divergent reaction of the first generation dendrimer with para -aminobenzoic acid. The crude product was purified by column chromatography on silica gel. The obtained dendrimer, HCD, was characterized by FT-IR and 1 H-NMR. The hexanuclear Ru(III) complex, [Ru 6 (HCD)(Cl) 12 (DMF) 12 ] was prepared by reaction of HCD with ruthenium(III) chloride hydrate and purified by column chromatography on alumina. Finally, [Ru 6 (HCD)(Cl) 12 (DMF) 12 ] was immobilized on a silica support. The Ru(III) ions in the silica-supported Ru(III) dendrimer were reduced by NaBH 4 in 2-methoxyethanol. The prepared Ru nanoparticles were characterized by ATR-IR, BET, XRD, FE-SEM, HR-TEM, and ICP. The mean size of the dendrimer-encapsulated metallic ruthenium nanoparticles was found to be 30-35 nm. The metallic ruthenium nanoparticles were then used as a heterogeneous catalyst for the hydrogenation reaction of citral to 3,7- dimethyloctanol at a temperature range of 90-120°C and a H 2 pressure of 14 bar in an autoclave reactor. The obtained products were characterized by gas chromatography and mass spectrometry (GC/MS). By increasing the reaction temperature at a constant pressure of H 2 , the yield of 3, 7- dimethyloctanol increases. In project II, the first generation dendrimer was obtained using the same method mentioned above. A second generation dendrimer was prepared by a divergent reaction of the first generation dendrimer with ortho-aminopyridine. The crude product was purified by column chromatography on silica gel. The final product, HPD, was characterized by FT-IR and 1 H-NMR. The hexanuclear Cu(II) complex, [Cu 6 (HPD)(DMF) 24 ](TFA) 12 , was prepared by reaction of HPD with copper(II) chloride hydrate in the presence of Ag(TFA) at room temperature in DMF. For preparation of the metallic copper nanoparticles, [Cu 6 (HPD)(DMF) 24 ](TFA) 12 was reduced by NaBH 4 in 2-methoxyethanol. The dendrimer-encapsulated metallic copper nanoparticles were characterized by ATR-IR, BET, XRD, FE-SEM, HR-TEM, and ICP. The average size of the metallic copper nanoparticles was found to be 35-40 nm. Finally, the dendrimer-encapsulated copper metal nanoparticles were used as a heterogeneous catalyst for the reduction reaction of 4-nitrophenol to 4-aminophenol in 2-methoxyethanol. The reaction progress was monitored by recording of the UV-Vis spectra at different times.