The molecule consists of two dimethylarsino groups attached to adjacent carbon centers of a benzene ring.

Work on diars preceded the development of the chelating diphosphine ligands such as dppe, which are now prevalent in homogeneous catalysis.

It was first described in 1939,[2] but was popularized by R. S. Nyholm for its ability to stabilize metal complexes with unusual oxidation states and coordination numbers, e.g. TiCl4(diars)2.

High coordination numbers arise because diars is fairly compact and the As-M bonds are long, which relieves crowding at the metal center.

[3][4] Diars is prepared by the reaction of ortho-dichlorobenzene and sodium dimethylarsenide:[5] It is a colorless liquid.