Summary: As our knowledge of materials at the nanoscale has grown, so has our knowledge of how to structure such devices at the nanoscale. After all, it is the two acting in concert – the material and the structure – that gives rise to functionality. The area of functional materials has a third knob – what happens if we can actively change how the material behaves? That’s how silicon chips work. In this talk, I will talk about other classes of functional material that can manipulate light and electricity. And if one can do that actively, using new device structures, there are many possibilities – especially as one reduces volumes to nanoscale dimensions, the energy requirement reduce dramatically, opening up a tantalizing range of possibilities – I will talk about two such possibilities and how device design is crucial.