Metropolitan Police said they were treating the separate attacks within 90 minutes on Thursday night as linked.
The assaults involved the pair attacking other moped riders and allegedly trying to steal their bikes.
Police are appealing for witnesses and anyone who has video of the incidents to contact them.
At the start of the rampage, a 32-year-old moped driver was approached as he drove towards the Hackney Road junction with Queensbridge Road.
The two male suspects are said to have tossed the substance in his face before one jumped on his moped and rode away.
Police said the man went to an east London hospital and they are waiting for an update on his injuries.
Four attacks took place in east London, and one in north London Twenty minutes later, at 10.50pm, another victim was sprayed with liquid on the Upper Street junction with Highbury Corner, Islington.
Source: Arrest after five acid attacks in London
