Commission H2 Astrochemistry is an upgrade of a long-running and successful Working Group of the same name.  The topic reflects one of growing importance within astronomy – the use of molecular emission and absorption lines to probe objects as diverse as planetary atmospheres and comets within our Solar System to distant galaxies at redshift greater than 6.  In addition to the intrinsic value of studying astrochemistry to astronomy, there is an additional benefit to chemistry in that conditions in the interstellar medium are so extreme in terms of temperature, densities, size and time scales not easily accessible to terrestrial laboratories. Thus astrochemistry attracts scientists from a number of different disciplines such as chemistry and planetary science.  It directly connects with new fields such as astrobiology and the study of exoplanets and their atmospheres. Because of this broad perspective, astrochemistry is a rich and vibrant field and the purpose of the Commission is to promote such connections.