Both were taken to an east London hospital for treatment after the unknown liquid was thrown at them in Roman Road, E2.
Pictures on social media show the men being helped by firefighters - and images show a jacket with its material singed.
Eye witnesses to the incident state that police officers were flagged down by two men who claimed they had been sprayed with acid.
And another man without a shirt could be seen sitting nearby as he was checked over by ambulance workers.
The pair, believed to be in their late teens, were attacked with a "noxious substance" in Roman Road at around 7pm yesterday.
They were given medical assistance at the scene and taken to a local hospital with burns.
"No arrest have been made and inquiries are ongoing".
A Metropolitan Police spokesman said: "We have been guided by the NHS, and the key treatment for these injuries is to flush the injury with lots of water". They were crying and saying: "Put the water on me".
Scotland Yard said the incident is being treated as a "suspected noxious substance attack". There were five linked acid attacks by men on mopeds.
Five acid attacks were carried out in under 90 minutes across Hackney, Stoke Newington and Islington on Thursday 13 July, with one victim suffering from "life changing injuries".
The Metropolitan police has given response vehicles 1,000 acid attack kits this week after the rise in such crimes.
The acid incidents are known as "face melters" after convicted acid attackers Billy and Geoffrey Midmore threw acid on 37-year-old mother-of-six Carla Whitlock.
On Saturday, the Daily Mail spoke to a gang member, named "Off", the people were choosing acid attacks over weapon attacks as the is no penalty for being caught in possession of acid-based chemicals as opposed to a knife or a gun.