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Skeletal formula
Ball-and-stick model
IUPAC name
Other names
694-87-1 YesY
ChemSpider 62868 N
Jmol-3D images Image
PubChem 24850072
Molar mass 104.15 g·mol−1
Density 0.957 g/cm3
Boiling point 150 °C (302 °F; 423 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Benzocyclobutene (BCB) is a benzene ring fused to a cyclobutane ring. It has chemical formula C8H8.[1]

BCB is frequently used to create photosensitive polymers. BCB-based polymer dielectrics may be spun on or applied to various substrates for use in Micro Electro-Mechanical Systems (MEMS) and microelectronics processing. Applications include wafer bonding, optical interconnects, low-K dielectrics, or even intracortical neural implants.


The Benzocyclobutene moiety has also appeared in a number of drug molecules. As an example, the amphetamine derived compound appears in the following patent:[2]

Also see S33005 and the benzocyclobutene analog of 2-cb was prepared by Nichols et al.[3]


Benzocyclobutene is a strained system which, upon heating to approximately 180 °C, causes the cyclobutene to undergo a conrotatory ring-opening reaction, forming o-xylylene. Since this process destroys the aromaticity of the benzene ring, the reverse reaction is highly favoured.

Thermal generation of o-xylylene from benzocyclobutene

o-Xylylenes generated in this way have been used prolifically in cycloaddition reactions, which restore the aromaticity to the benzene ring, while forming a new annulated species.[4]

See also[edit]


  1. ^ 164410 Benzocyclobutene 98%
  2. ^ U.S. Patent 3,149,159
  3. ^
  4. ^ Mehta, G.; Kotha, S. Recent chemistry of benzocyclobutenes. Tetrahedron Lett. 2001, 57.