Logic gates, the basic elements of the digital world, can now be built using one single molecule. An example is XOR, with two inputs. If at least one of them is “1,” then the output is “1,” as well; otherwise, it is 0. These logic gates measure less than 2 nanometers. They are based on single-electron transistors, capable of assembling and organizing themselves on a surface. Molecular logic not only reduces the on-chip dimensions and lowers energy consumption, they may also have similarities to the way the brain processes signals, says Prof. Christian Nijhuis, who published his results in Advanced Materials.