Seaweeds are vital resources with economic, societal, and environmental values. These are inhabited in different climatic zones of the oceans. The major factors affecting seaweed distribution are temperature, tidal height, salinity, sea level rise, carbon dioxide (CO 2 ) concentration, and ultraviolet (UV) radiation.Typically, seaweeds are considered a critical source of bioactive compounds that have broad applications in food, cosmetic, medical, and agricultural fields. Presently, nanomaterials are gaining more attraction in medicine, environment, and food and cosmetic industry. Several metallic nanoparticles (silver and gold) are synthesized from seaweeds. The yield of the bioactive compounds mainly depends on the seaweed species and the extraction method employed. Hence, updated knowledge on these aspects is required for further research. Based on the research outcomes published in journals indexed in Scopus, Web of Science, and regional journals, this review addresses (a) the extraction of bioactive compounds present in seaweeds, (b) the applications of the bioactive compounds obtained from seaweeds, (c) synthesis and applications of biochar and nanomaterials, and (d) application of seaweed extract for crop growth.