In this thesis we report studies of thin metal films of Ag and Au on Si(111) surface. All experiments are carried out in an ultra high vacuum system via STM measurements. Data and analysis for different ranges of coverage and anneal temperature are presented followed by an in depth discussion. Particular focus is given to surface structure, mobility, surface reconstruction, potential catalytic properties and self assembly. Newly acquired insights are then extended to pentacene study on Ag/Si(111).