Metamaterial is engineered material with exotic properties not found in nature. We explore directed assembly and synthesis of optical metamaterials such as moire metamaterials and colloidal metamaterials for various applications. Roll-to-roll manufacturing is being developed to enable the cost-effective large-scale assembly of moire metamaterials. We have invented a class of optothermal tools to direct chemical reactions and assemble colloidal particles into targeted metamaterials. Inline multiscale metrology is applied to measure structures, dynamics and properties of metamaterials. We further explore metamaterials coupled with active molecules and atomically thin materials for function-enhanced devices.