A study of the self-organisation of metallic nanoparticles into assemblies of interest to the metamaterials community has been conducted. Numerous colloidal nanochemistry techniques were developed to fabricate structures of interest. Spectroscopic techniques were then employed to probe the optical properties and evaluate to what extent they could be used to advance metamaterials research. In particular, large scale planar arrays of metallic nanoparticles fabricated on a variety of functionalised substrates such as glass, silicon and polymers, as well as analogues prepared on microscale spherical substrates were studied. Bottom-up techniques were employed to build up structures into the third dimension, one of the principal challenges currently facing metamaterials researchers and the suitability of the planar structures for SERS applications was investigated. A magnetic resonance, a key building block of a number of metamaterials applications was identified in the spherical structures and the potential of these structures as cloaking devices was studied.