The CAS registry number of Coumarin is 91-64-5. The systematic name is 2H-chromen-2-one. In addition, it is a fragrant chemical compound of benzopyrone found in many plants with the molecular formula C₉H₆O₂. What's more, it has a sweet odor, and readily recognised as the scent of newly-mown hay. So it can be used in perfumes.

Physical properties about this chemical are: (1)ACD/LogP: 1.39; (2)ACD/LogD (pH 5.5): 1.39; (3)ACD/LogD (pH 7.4): 1.39; (4)ACD/BCF (pH 5.5): 6.705; (5)ACD/BCF (pH 7.4): 6.705; (6)ACD/KOC (pH 5.5): 135.881; (7)ACD/KOC (pH 7.4): 135.881; (8)#H bond acceptors: 2; (9)Polar Surface Area: 26.3 Å²; (10)Index of Refraction: 1.595; (11)Molar Refractivity: 39.767 cm³; (12)Molar Volume: 117.097 cm³; (13)Polarizability: 15.765 ×10^-24cm³; (14)Surface Tension: 46.411 dyne/cm; (15)Density: 1.248 g/cm³; (16)Flash Point: 118.268 °C; (17)Enthalpy of Vaporization: 53.789 kJ/mol; (18)Boiling Point: 297.999 °C at 760 mmHg; (19)Vapour Pressure: 0.001 mmHg at 25°C.

Preparation of Coumarin: it can be prepared in a laboratory in a Perkin reaction between salicylaldehyde and acetic anhydride. The reaction needs solvent potassium carbonate and the temperature should be controlled at 210-212 °C. After the reaction, via a series of washing, vacuum distillation and recrystallization by ethanol you can get the desired product.

Uses of Coumarin: It has been used as aroma enhancer in pipe tobaccos and certain alcoholic drinks. And it is used in the pharmaceutical industry as a precursor molecule in the synthesis of a number of synthetic anticoagulant pharmaceuticals similar to dicoumarol. In addition, it is also used as a gain medium in some dye lasers, and as a sensitizer in older photovoltaic technologies. Moreover, it can be used to get chromene-2-thione. This reaction will need reagent bis(1,5-cyclooctanediylboryl) sulfide and solvent heptane. The reaction time is 2 hours by heating. The yield is about 80%.

When you are using this chemical, please be cautious about it as the following:
This chemical is harmful by inhalation, in contact with skin and if swallowed. It is irritating to eyes, respiratory system and skin. In addition, it may cause sensitization by skin contact and is moderately toxic to the liver and kidneys. When you are using it, wear suitable protective clothing and gloves. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

You can still convert the following datas into molecular structure:
(1)SMILES: c1ccc2c(c1)ccc(=O)o2
(2)Std. InChI: InChI=1S/C9H6O2/c10-9-6-5-7-3-1-2-4-8(7)11-9/h1-6H
(3)Std. InChIKey: ZYGHJZDHTFUPRJ-UHFFFAOYSA-N

The toxicity data is as follows: