The instant invention provides a polymerization process for producing ethylene based polymers.In one embodiment, the instant invention provides a polymerization process for producing ethylene based polymers comprising: polymerizing ethylene with optionally one or more α-olefins in the presence of one or more first catalyst systems and optionally one or more second catalyst systems in a dual reactor system or a multiple reactor system, wherein first catalyst system comprises; (a) one ore more procatalysts comprising a metal-ligand complex of formula (I):