New technologies for enhancing electronics and photonics are crucial for emerging applications in energy, sensing, artificial intelligence, and countless other areas. But these technologies are hard to come by using traditional semi-conductors. Over the past decade, so-called third-generation semi-conductors have proved to be a boon to material science and engineering, giving researchers increased versatility in boosting device performance. Among the most promising properties of these materials is piezoelectricity, the ability to convert mechanical energy to electrical energy and vice versa. The December 2018 issue of the MRS Bulletin takes a look at how researchers are exploiting piezoelectricity in semi-conductors to enhance electronic and photonic devices like never before, providing a glimpse into the world of piezo-tronics and piezo-phototronics. In 2006, Zong Lin Wang's group at George Attack discovered that piezoelectricity in zinc oxide nanowires exerts a gating effect like that in transistors. Since then, researchers have sought to incorporate mechanical sensitivity into traditional electronics, providing a new lever of sorts with which to modulate device performance. Today, that piezo-tronic effect is helping researchers create increasingly responsive biochemical, gas, and humidity sensors, for instance. For gated optoelectronic devices such as LEDs, photo sensors, and solar cells, the piezo-phototronic effect is proving just as valuable. The coupling of piezoelectricity, semi-conductor transport, and light matter interaction enables researchers to engineer the behavior of photo-generated carriers mechanically. The result is a new class of devices that are uniquely adaptive and intuitive, suitable for applications in sensing and human machine interfacing. The piezo-phototronic principle is also helping researchers engineer the interfaces between semi-conductors and electrolytes to yield more efficient photo anodes and improved photo-catalists for chemical and biochemical reactions. Although one-dimensional materials have been the primary medium for realizing piezo-tronic and piezo-phototronic effects, two-dimensional material applications are rapidly emerging. Research suggests the feasibility of coupling piezo-effects with the exotic properties native to 2D materials, such as quantum transport and topological properties. Further advancements in piezo-tronics and piezo-phototronics will require a much better understanding of the underlying physics that governs the operation of such devices. In turn, more sophisticated methods for designing, fabricating, and characterizing materials that support piezo effects are needed. But with the potential to revolutionize modern energy sensing a human integrated technologies, the future of this emerging area of materials research looks bright. For more information about these and other advances, check out the December 2018 issue of the MRS bulletin.