Salicylates are the class of compounds that are widely valued for their pain killing, antipyretic and anti-inflammatory properties. The most commonly known and used salicylates are salicylic acid. They are used extensively for the relief of headache, inflammation, arthritis pain, and some are employed in the treatment of heart attacks and strokes in the elderly. Recently, salicylic acid has been used primarily as an intermediate in the production of agrochemicals, dyes and colorant products. In addition to analgesic, antipyretic, and antiinflammatory properties, salicylates possess also some other actions that have been proven to be therapeutically beneficial. Pharmacological effects and biotransformation pathways of salicylic acid and its derivatives are well known, and the effects of the structural features on the physico-chemical properties and on the bioactivity of these compounds were investigated in numerous theoretical and experimental studies More attention has been recently paid to the ability of salicylates to inhibit platelet aggregation.A recent patent reported that benzoic acid derivatives have good anti-tumor properties, their activity being related to novel synergistic compositions that selectively control tumor tissue. Salicylic acid and its derivatives have recently become attractive to theoreticians as well as experimentalists since their structures are of some biological significance particularly in medicinal and enzyme chemistry. Salicylates have long been known as water soluble compounds derived from a number of plants, particularly Willow and Meadowsweet with analgesic, antipyretic and anti-inflammatory properties. Following the identification of salicin as the active principle of Willow bark, and the subsequent synthesis of acetylsalicylic acid (aspirin), the use of natural salicylates has declined. The most important is acetylsalicylic acid, or aspirin. Sodium salicylate also has been used systemically, and it exerts similar effects. Many of the actions of aspirin appear to result from its ability to inhibit cyclooxygenase, a rate-limiting enzyme in prostaglandin biosynthesis. Therefore one of the purposes of this project is the synthesis of selected new mono hydroxy and disalicylate derivatives of these compounds. In this project, friedel-crafts reaction of hydroquinone with methyl chloroformate and acetic anhydride was utilized for the synthesis of new derivatives of salicylates. The effect of catalyst type and amount, temperature and reaction time were investigated in order to optimizing the overall reaction yields. For this purpose aluminium chloride, ferric chloride, nickel dichloride, zinc chloride and boron trifluoride were used as catalyst. Also, ionic liquid (3-Carboxy piridinium hydrogen sulphate) friendly green chemistry and heterogeneous montmorilonite-k10 were used. The structure of all the synthesized compounds were analyzed by GC/MS, MASS and characterized by 1H-NMR, 13C-NMR and FT-IR. Aromatic azo molecules have been traditionally used in dye and food industries. In theoretical section of this project, the structure of (4-(sulfonyl azide) phenyl)-1- azide, all possible nitrene intermediate and products with norbornene were optimized theoretically by performing HF and B3LYP levels of theory using the standard 6-311+G* basis set. Conformational analysis of these compounds was performed. So the most stable and least stable conformers of these compounds were determined. The energy barrier of the rotation around azide bonds with the phenyl group in products was calculated.