The process of assembling metal nanoparticles at the interface of two liquids has received a great interest over the past few years due to a wide range of important applications and their unusual properties compared to bulk materials. The work in this thesis presents a low cost, simple and cheap synthesis of metal nanoparticles, core/shell structures and semiconductors followed by assembly of these particles between immiscible liquids. The aim of this thesis is divided to three parts (Summary of the experimental work of this thesis is in Table A1):1) To achieve a closed loop recycling for producing cadmium sulfide as powders and/or nanostructured thin films for solar cells or other optoelectronic devices applications. A series of bis(dialkyldithiocarbamato)cadmium(II) were used for this approach. Bis(dioctyldithiocarbamato)cadmium(II) complexes proved to be the optimal alkyl chain for this process. The approach can be extended to other metal sulfides such as those of Zn, Pb, Cu, or Fe and many transition metals and oxides.2) To explore the phenomena of exchange bias in very small size particles (5 nm) of Ni/NiO (core/shell structure) obtained by solution phase synthesis. Ferromagnetism (FM) due to exchange bias is well established in the case of larger particles with diameters over 10 nm. However, sub 10 nm magnetic structures synthesized by solution phase have never been found to be ferromagnetic at room temperature. These Ni/NiO nanocrystals with ferromagnetic properties at room temperature were among the smallest and strongest magnets made in solution. Similar magnets can be obtained using a rare class of high anisotropy materials nearly all of which feature precious metals. This work would lead to significantly cheaper magnetic particles suited for the mass market. The applications of this work can be applied to produce viable storage devices and the other possibility is to disperse these nanocrystals in solution and use it to make ferrofluids which have a number of mature applications. Functional device architectures of these particles were rapidly and inexpensively produced as thin films using self-assembly of liquid/liquid interface process at room temperature by using octylamine as a surfactant.3) To synthesise and assemble submicron particles of silver, cobalt and nickel by using polyol methods and liquid/liquid interface, respectively. The effect of reaction conditions (solvent, precursor concentration, temperature, etc.) on synthesis and assembly of the particles was studied. Assembled cobalt and nickel as films are promising materials for spintronics, magnetic and magneto-electronics and biomedics. The nature and characteristics of the particles and their films were studied by a number of techniques such as SEM, EDX, TEM, p-XRD, UV-Vis, PL, FTIR, DLS and SQUID for magnetic measurements.