Fueled by a wide range of possibilities to tune their interactions with light, a strong increase of interest could be witnessed in the field of plasmonic nanoparticle research in the recent years. The adjustable size, geometry and spatial arrangement to each other enables to control the optical response of such nanostructures at will. This translates into a plethora of potential applications for medicinal therapy, analytics, catalysis, energy conversion and even for devices with completely artificial optical properties. In order to obtain the building blocks for these materials, strategies to synthesize well-defined particles and their assemblies are required. The present thesis deals with the synthesis and characterization of plasmonic nanoparticles and their assemblies. Rigid-rod linkers based on oligo(phenylene-ethynylenes) could be utilized for the formation of small clusters like nanoparticle dimers. The synthesis of tripodal thioacetates for the preparation of functional SAMs on gold surfaces was performed. Polymer protected gold particles could be synthesized via the Diels-Alder reaction of maleimide@Au particles with a poly(2-vinylpyridine)-block-poly(ethylene oxide) block copolymer bearing a single furan group. Au-PEI and Au-Ag core-shell clusters with tunable optical properties were prepared which could serve as promising building blocks for metamaterials. Block copolymer lithography in combination with a cyclic complexation-reduction approach could be utilized to create ordered plasmonic nanostructures on micrometer surface areas.