The present chapter touches the major themes of the environmental and economic uses of macroalgae outlining their current roles and future potential. Ecologically, seaweeds serve as vital primary producers and contribute significantly to carbon sequestration, shoreline protection, habitat formation, and the mitigation of declining oxygen levels and increasing ocean acidity. As such, they are increasingly recognized as a promising blue carbon strategy for climate change adaptation and modification. Additionally, they serve as valuable model organisms for studying the impacts of pollution on aquatic ecosystems due to their ability to absorb toxic substances and transform waste into valuable products also makes them important agents in the biological purification of wastewater, offering sustainable solutions to environmental challenges and providing a solution to climate change. From an economic perspective, seaweeds are emerging as a viable alternative to synthetic ingredients, contributing to diverse sectors such as nutrition, pharmaceuticals, cosmetics, dyes, paints, and biotechnology. They also store carbohydrates as metabolic reserves, making them a sustainable source for biofuel production. Furthermore, seaweeds enhance agricultural productivity and function as multifunctional bioinoculants suitable for organic farming. However, researchers must also address the challenges associated with extracting bioactive compounds, aiming to develop cost-effective methods for solubilizing these valuable molecules and utilizing them as natural ingredients across various industries.