The two men were both rushed to hospital with burns following the broad daylight horror in Hackney at around 7.20pm yesterday.
They remain in a non life threatening condition in hospital and no arrests have been made so far.
It came just hours after cops were raced to another acid attack in nearby Walthamstow.
A man was walking on Walthamstow High Street just after 6.30am when two men wearing burkhas chucked the substance over him.
They then fled the scene in a waiting car, with cops still hunting the suspects.
The UK has one of the highest rates of acid attacks per capita in the world, according to Acid Survivors Trust International (ASTI).
It claims the country does not have "tight controls on acid sales" or "legislation specific to acid attacks".
ASTI's figures, quoting the police, reveal the number of recorded attacks has increased nearly three-fold from 228 recorded crimes in 2012 to 601 attacks in 2016.
Gang disputes are said to be behind the rise in acid attacks in London and other British cities.
London has emerged as a hot spot for acid attacks in recent years, with more than half of incidents within the UK taking place in the capital.
The number of cases more than doubled from less than 200 in 2014 to 431 in 2016, with Scotland Yard focusing on specific parts of the city.