Abstarct: The ternary compound of copper tin sulfide, Cu2SnS3 (CTS), and quaternary compound of copper zinc tin sulfide, Cu2ZnSnS4 (CZTS), is among the promising candidates for photovoltaic applications. The sulfur-containing compounds of CTS and CZTS have attracted much attention in the field of thin-film solar cells due to being comprised of non-toxic, non-expensive, naturally occurring and abundant elements, as well as having direct energy bandgaps within 1.4-1.6 eV and high absorption coefficients above 104 cm-1. According to the literature, the challenges faced during the production route of CZTS and CTS, as clusters, nanostructures and thin films, are controlling phase and structure, removing secondary phases, controlling elemental ratio, structural stability, optimal method for the synthesis of films, appropriate conditions of film annealing, controlling thickness and film uniformity. In the present dissertation, we intended to address the existing problems and sparse reports on the synthesis and analysis of CTS and CZTS. Here, we synthesized the nanoparticles via the chemical method of solvothermal and prepared the thin films of them by the simple method of drop casting. Our goals in studying the above-mentioned issues are to create a set of basic, useful, practical and not examined concepts in the field of empirical physics on CTS and CZTS nanoparticles. Following issues were investigated on the ternary compound of CTS and the thin films prepared from it due to the lack of continuous and regular reports: 1. The presence and amount of PVP as a stabilizing or capping agent resulted in the change of particles’ size and shape and the creation of a hydrophilic surface (which itself resulted in the fast dissolution of nanoparticles in aqueous solvents and creation of a stable ink for the preparation of thin films). 2. It was observed that by increasing reaction temperature, particles’ size increases, particles’ morphology becomes more uniform (spherical particles), bandgap energy increases, and Sn amount increases. 3. When copper acetate was substituted, the structure was changed from tetragonal to hexagonal, amorphous particles were formed, and Cu4S7 impurity was observed. 4. Due to their increased size and changed elemental ratio after annealing, thin films prepared from nanoparticles have a bandgap energy and exhibit a lower resistivity than the nanoparticles. In the quaternary compound of CZTS and thin films of them, the following issues were investigated: 1. Investigation of reaction temperature and elemental ratio in the nanoparticles reveals the increased size and increased Sn amount, and in the thin films reveals that annealing in Argon results in the increased crystallinity and increased size, whereas annealing in Argon/Sulfur results in a thicker, denser surface without cracks. 2. Substitution of copper acetate and zinc acetate and the increase of reaction temperature result in the formation of hexagonal structure with a bandgap energy narrower than it is in the tetragonal structure, and the elemental ratio becomes more optimal as reaction temperature increases. 3. The increase of iron amount in the alloy compound of Cu2ZnxFe1-xSnS4(CZFTS) results in the structural transition from kieserite to stannite, the decrease of bandgap energy, and the red shift of Raman peaks and shows a bowing parameter representing miscibility by preserving good properties, and also the thin films annealed in Argon show an increased crystallite size and a decreased resistivity after annealing. However, the annealed films with their increased amount of iron show an increased resistivity, because iron has a lower electrical conductivity than that of zinc.