Wearable and flexible electronics requires energy efficient materials and devices with excellent flexibility for the active and passive components. Many nanostructured materials possess high surface-to-volume ratio, mechanical flexibility and low power consumption. These intriguing properties can be harnessed for a variety of applications in electronics and photonics. In the past, we have fabricated an assortment of arrayed nanostructures using a variety of materials from inorganic semiconductors to organometal perovskite materials. These nanomaterials can be fabricated with chemical vapor deposition method and/or printable method with scalability. Meanwhile, the materials have been fabricated into various flexible optoelectronic devices, including photodetectors and solar cells. The study has shown that three-dimensionally (3-D) arrayed nanostructures can help to improve solar cell device energy conversion efficiency, as well as the flexibility. However, rational design and proper structural optimization is not trivial. Using printable method and template guided growth method, semiconductor nanowires have been fabricated into planar arrays and 3-D arrays for photodetectors. Proof-of-concept flexible image sensor devices with high density 3-D nanowire arrays have been fabricated. Meanwhile, flexible energy storage devices have also been fabricated using nanostructured materials to enhance storage capacity for wearable devices. Overall, the nanostructure integration methodology that we developed may enable many applications on electronics and optoelectronics in the future.