Boron trifluoride is the chemical compound with the formula BF3. This pungent colourless toxic gas forms white fumes in moist air. Boron Trifluoride (BF3) is one of the strongest Lewis acids (or electron pair acceptors) known and, therefore, finds broad application as an acidic catalyst for organic synthesis reactions. As an electron acceptor, BF3 readily reacts with chemicals containing Oxygen, Nitrogen, Sulfur, and other electron pair donors to form addition or coordination compounds. It is soluble in concentrated nitric acid, benzene, dichlorobenzene, chloroform, carbon tetrachloride, carbon disulfide. Anhydrous boron trifluoride has a normal boiling temperature of -100.3 C and a critical temperature of -12.3 C, so that it can be stored as a refrigerated liquid only between those temperatures. BF3 should be stored in gas cylinders away from heat in a ventilated place. Application: because of its potency as a lewis acid and its greater resistance to hydrolysis compared to other boron trihalides, boron trifluoride is widely used as a catalyst for organic synthesis reactions such as in polymerization of olefins or diolefins, vinyl ethers or esters, terpenes or derivatives, unsaturated acids or esters, heterocyclic unsaturated organics e.g., indene, coumarone, etc., styrene or derivatives with isoprene, butadiene, 1, 3-pentadiene, etc. in alkylation of aromatic hydrocarbons, phenols with olefins, phenols with alcohols, in isomerization of paraffins, unsaturated hydrocarbons, in synthesis of acetals and ketals, indoles, steroids and intermediates, alpha – methoxymercurials, hydroxy fatty acids etc. It also aids in cyclization of natural and synthetic elastomers, disproportionation of isoparaffins. It can be used as a reagent for desulfurizing solvents and intermediates, desulfurizing cracked petroleum distillated, separating xylene isomers, absorbing water of nitration etc. It is also used in metallurgy, as flux and antioxidant. Boron Trifluoride is prepared by a two-stage process reaction of boron containing material and a fluorine containing substance in the presence of an acid. The traditional raw material used is borax, fluorspar and sulphuric acid. The Indian production level is around 2400 tonnes per annum. Boron Trifluoride is used extensively as a catalyst in such diverse operations as isomerization, alkylation, polymerization, esterfication, condensation, cyclization, hydration dehydration, sulfonation, desulfurization nitration, halogenation oxidation and acylation. While BF3 would continue to remain relevant in their application areas, the growth in demand are unlikely to be significant in the immediate future, in view of the substitution possibilities for boron trifluoride, which is considered to be a toxic product.