This paper presents the combination of "bottom-up" layer-by-layer (LbL) nano self-assembly and "top-down" micromanufacturing techniques for MEMS and microelectronics applications. Two approaches, modified lift-off and metal mask, were utilized to pattern nano-assembled thin films effectively. With nano self-assembly and surface micromachining, highly flexible nanoparticle-based magnetic cantilever platform for micro sensing and actuation was self-assembled. Self-assembled magnetic thin films on polymeric tunneling sensors were functional as a polymer actuators for the actuation of highly sensitive sensors. For microelectronics devices, self-assembled silica nanoparticle thin film acted as the dielectric layer for field-effect transistors. Nanoparticle- and polymer-based field-effect transistors with embedded nano self-assembled films as dielectric and active layers were fabricated and characterized successfully as well.