Imidoyl halides are synthesized by combining amides and halogenating agents.  The structure of the carboxylic acid amides plays a role in the outcome of the synthesis. Imidoyl chloride can be prepared by treating a monosubstituted carboxylic acid amide with phosgene.
:RC(O)NHR’ + COCl → RC(NR’)Cl + HCl + CO
Thionyl chloride is also used.
Imidoyl chlorides are generally colorless liquids or low-melting solids that are sensitive to both heat and especially moisture. In their IR spectra these compounds exhibit a  characteristic ν band near 1650–1689 cm. Although both the syn and anti configurations are possible, most imidoyl chlorides adopt the anti configuration.