Molecular structure of 5-Cyanophthalide (CAS NO.82104-74-3) is:

Product Name: 5-Cyanophthalide
CAS Registry Number: 82104-74-3
IUPAC Name: 1-Oxo-3H-2-benzofuran-5-carbonitrile
Molecular Weight: 159.1415 [g/mol]
Molecular Formula: C₉H₅NO₂
XLogP3: 0.5
H-Bond Donor: 0
H-Bond Acceptor: 3 
EINECS: 279-900-2
Melting Point: 201-205 °C(lit.) 
Surface Tension: 60 dyne/cm
Density: 1.36 g/cm³
Flash Point: 199.3 °C
Enthalpy of Vaporization: 65.94 kJ/mol
Boiling Point: 407.5 °C at 760 mmHg
Vapour Pressure: 7.53E-07 mmHg at 25°C
Product Categories: Phthalides; Intermediatesofcitalopram; API intermediates; Aromatics Compounds; Aromatics; Miscellaneous Reagents

 5-Cyanophthalide (CAS NO.82104-74-3) is a useful synthetic intermediate.

Safty information about 5-Cyanophthalide (CAS NO.82104-74-3) is:
Hazard Codes: Xn,Xi
Risk Statements: 20/21/22-36/37/38 
R20/21/22:Harmful by inhalation, in contact with skin and if swallowed. 
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements: 36/37-36-26 
S36/37:Wear suitable protective clothing and gloves. 
S36:Wear suitable protective clothing. 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
WGK Germany: 3

 5-Cyanophthalide , its cas register number is 82104-74-3. It also can be called 1,3-Dihydro-1-oxoisobenzofuran-5-carbonitrile .It is a white to pale yellow crystalline solid.