Symposium D, "Compound Semiconductors for Energy Applications and Environmental Sustainability," was held at the 2011 MRS Spring Meeting April 25-29 in San Francisco, California. Compound semiconductors have long been an integral part of everyday life. Many of these semiconductors exhibit direct band gaps that are tailorable over a wide range of energy. This property can be leveraged for many energy-related applications such as efficient lighting, high-efficiency solar cells, and efficient switching. Recent progress on their potential as emitters, sensing devices in biological and chemical...