This book presents a comprehensive exploration of the sustainable nature of perovskite multiferroic materials, offering an in-depth discussion on both single-phase and composite perovskite-based multiferroics, as well as their nanostructures and structural aspects. A strong emphasis is placed on the practical applications of these emerging nontoxic materials, particularly in energy harvesting, green synthesis techniques, and advanced technological applications. Key topics covered include the role of perovskite multiferroics in spintronics, photovoltaics, photocatalysis, sensors, gyrators, gradiometers, transducers, and memory storage devices. Recent breakthroughs in these fields, including their potential contributions to quantum computing, make this an essential resource for scientists and young researchers seeking inspiration and innovative ideas for future advancements. A special focus is given to lead-free, eco-friendly multiferroic materials, highlighting their significant role in sensors and actuators for nano- and microelectromechanical systems. The book also explores the high-quality performance of magnetoelectric coupling-based micro/nano-electromechanical devices, which can be integrated with radio frequency circuits. By providing an in-depth analysis of green, nontoxic, and commercially viable multiferroic and magnetoelectric technologies, this book serves as a crucial guide for materials scientists, solid-state physicists, and chemists. Researchers working in energy harvesting, spintronics, photovoltaics, photocatalysis, and quantum computing will find valuable insights that bridge fundamental concepts with the latest advancements in the field.