The Sultanate of Oman's coastline is abundant in many natural raw materials, such as seaweed plants. Red seaweeds are rich in a variety of nutrients, including lipids, minerals, vitamins, polyphenols, and carbs. These substances have a variety of uses in the food industry as well as in pharmaceutical, nutraceutical, and cosmetic products. A significant amount of agar was discovered to be present in Gracilaria debilis species that belong to the Rhodophyta group (Red seaweed). This study aimed to determine the proximate composition of the species Gracilaria debilis, extract its organic solvent-soluble compounds as well as investigate its polyphenols contents (TPC, TFC, and TTC), and extract agar and study its functional, biological and chemical properties. The non water-soluble molecules were extracted using three different organic solvents sequentially (ethyl acetate, acetone and methanol). The agar was extracted by hot water (90oC for 2h). High Performance Liquid Chromatography (HPLC) was performed to study the monosaccharide composition of agar and profiling. The structural characteristics of the organic solvent extracts and agar were analyzed by Fourier Transform Infrared (FTIR-ATR) technique. The finding of this study showed that the ash (69.78 ± 1.98%) were the most abundant components in G. debilis, followed by carbohydrates (20.63 ± 2.00 %) and protein (8.09 ± 0.03%), and the lipid content was found the lowest (1.45 ± 0.03%). The main essential minerals found in the sample were Na, K, Ca, P, Fe, where the k was detected with the highest concentration (48.72 ± 0.67 mg/g). The methanolic extract exhibited the highest polyphenols contents (154.2 ± 4.58, 30.14 ± 0.20, and 409.35 ± 2.91 mg/g of TPC, TFC and TTC, respectively) among the three fractions. Methanol extracts (38 ± 0.40 U/ml) showed higher value of antioxidant capacity with hydrogen peroxide than ethyl acetate (33.6 ± 0.69 U/ml) and acetone (30.66 ± 1.61 U/ml) extraction. The total yield of agar was 21.4 ± 0.812%. The agar showed a high antioxidant capacity at 0.9 % of extracted agar and gel strength (120.1±5.3 g/cm2 ) at 2.0% of KCl concentration. Polysaccharides in agar from G. debilis mainly consist of Galactose (65.75 ± 1.61%), glucose (18.80 ± 2.49 %), with small amounts of mannose, glucuronic acid, glucuronic acid, galacturonic acid, xylose fucose, and arabinose. In addition, the structural characteristics demonstrated presence of ester sulfate (1380 -1355 cm-1), Galactose 4- sulfate (850-845 cm-1) and Galactose 6-sulfate (820 cm-1) structures in the agar extract where, the sulfate content was found (12.13 ± 0.73%). In conclusion, significant amounts of polyphenols were discovered in the organic solvent extracts from G. debilis, Furthermore, the agar composition displayed excellent functional, biological, and chemical characteristics. Where it can be utilized in food industry as thickening, gelling, stabilizing, and antioxidant agents. Future research could also concentrate more on protein extraction from G. debilis and investigate its biological, chemical, and functional characteristics.