Homoleptic allyl derivatives of many Main-Group and transition metals, M(C,H,),, are readily available through one-pot syntheses using metal halides and allyl Grignard reagents or by alkylation of alkali-metal salts. The relatively low molecular weight of a C3H, ligand contributes to high vapor pressures whilst the stability of the allyl radical is predicted to reduce decomposition temperatures. These compounds represent a class of volatile precursors for organometallic chemical vapor deposition (OMCVD) of thin films. Film growth studies using iridium, molybdenum, palladium, platinum, rhodium, selenium, tellurium and tungsten compounds are reviewed and the relationships between pyrolysis pathways and film purity are discussed.