Two new oligomeric sulfone and sulfone-ketone containing phthalonitrile (PN) resins with excellent processability have been developed. The PN monomers were prepared from the reaction of an excess amount of bisphenol S with 4-(chlorophenyl)sulfone or 4,4-dichlorobenzophenone in the presence of a base in a solvent mixture (dimethylsulfoxide/toluene), followed by end-capping with 4-nitro-PN in a two-step, one-pot reaction. These PN resins exhibited good viscosities and cure times for molding into various shapes. After being thermally cured to yield crosslinked polymers, these polymers demonstrated superb mechanical properties, thermo-oxidative stability, and maintained good dielectric properties. Published 2016.