In article number 1702479, John A. Rogers, Jae-Woong Jeong, and co-workers develop a battery-free, wireless optofluidic neural system by integrating a multimodal neural probe consisting of micro-scale inorganic light-emitting diodes, and a microfluidic drug delivery system with a stretchable radiofrequency energy-scavenging circuit, into an ultracompact, lightweight and soft platform. The miniature neural implant can be fully implanted in the brain for in vivo wireless pharmacology and optogenetics.