Molecular structure of Coumarin 138 (CAS NO.62669-74-3) is:

Product Name: Coumarin 138
CAS Registry Number: 62669-74-3
IUPAC Name: 7-(dimethylamino)-2,3-dihydro-1H-cyclopenta[c]chromen-4-one
Molecular Weight: 229.2744 [g/mol]  
Molecular Formula: C₁₄H₁₅NO₂  
XLogP3-AA: 2.4  
H-Bond Donor: 0  
H-Bond Acceptor: 3
Index of Refraction: 1.615 
Molar Refractivity: 64.88 cm³ 
Molar Volume: 185.8 cm³
Surface Tension: 49.7 dyne/cm 
Density: 1.23 g/cm³ 
Flash Point: 173.9 °C 
Enthalpy of Vaporization: 68.11 kJ/mol 
Boiling Point: 426.3 °C at 760 mmHg
Vapour Pressure: 1.79E-07 mmHg at 25°C 
Canonical SMILES: CN(C)C1=CC2=C(C=C1)C3=C(CCC3)C(=O)O2
InChI: InChI=1S/C14H15NO2/c1-15(2)9-6-7-11-10-4-3-5-12(10)14(16)17-13(11)8-9/h6-8H,3-5H2,1-2H3 
InChIKey: RIUSGHALMCFISX-UHFFFAOYSA-N

 Coumarin 138 , its cas register number is 62669-74-3. It also can be called 7-Dimethylamino-2,3-dihydro-1H-cyclopenta[c]chromen-4-one ; 7-(Dimethylamino)-2,3-dihydrocyclopenta[c][1]benzopyran-4(1H)-one .It is a yellow to green-yellow crystals or flakes.