Treatment of 1,2,3,4,5-pentamethylcyclopenta-2,4-dien-1-yl arsenic(III) dichloride (II) with two equivalents of cobaltocenium fluoride or potassium iodide affords the analogous compounds Cp * AsF 2 (I) and Cp * AsI 2 (IV) in 85% and 98% yield respectively. Cp * AsBr 2 (III) has been synthesized by direct metathesis reaction between AsBr 3 and Cp * Li in 70% yield. The new compounds have been characterized by spectroscopic methods ( 1 H, 13 C, 19 F NMR, El-MS) and elemental analyses. The crystal structures ofI–IV were determined by X-ray diffraction methods. The AsX 2 -moiety inI–IV is σ-bound to the cyclopentadienyl ligand, indicating remarkable π-interaction with the diene fragment of the cyclopentadienyl ring. In addition, weak intermolecular contacts are observed inI andIV, completing the coordination sphere around the arsenic atom to pseudo-tetrahedral.