Small electronic circuits power our everyday lives, from the tiny cameras in our phones to the microprocessors in our computers. To make those devices even smaller, scientists and engineers are designing circuitry components out of single molecules. Not only could miniaturized circuits offer the benefits of increased device density, speed, and energy efficiency—for example in flexible electronics or in data storage—but harnessing the physical properties of specific molecules could lead to devices with unique functionalities. However, developing practical nanoelectronic devices from single molecules requires precise control over the electronic behavior of those molecules, and a reliable method by which to fabricate them.