The armed gang were caught on CCTV camera arriving at the scene in a black Ford Galaxy, before carrying out the late night attack on Tuesday (August 8).
The group sprayed a noxious substance at the victims before fleeing the scene.
Metropolitan Police has now released the CCTV footage to the public in a bid to identify a group of men following the violent robbery in East Finchley, which took place at around 10.55pm.
The victims - both men aged 21 and 26 - were in a parked car in Long Lane, at the junction with Trinity Road, when they were approached by six males wearing balaclavas and armed with knives.
The victims were assaulted and a Rolex watch and a wallet were stolen.
As the suspects left the scene on foot, a substance was sprayed at the pair.
Officers and London Ambulance Service attended the scene and the victims were treated for their injuries.
They suffered bruising and minor burns and were taken to hospital for treatment and were thankfully not seriously injured.
Initial testing of the substance established it was not acid but some form of noxious substance.
PC Dan Levy, the investigating officer from Barnet CID, said: "I am appealing to anyone who was in the area and witnessed this incident to speak to police.
"We know there were people in Long Lane at around the time of the incident and someone may have seen something significant that could assist our investigation."
There have been no arrests and enquiries continue.
Anyone with information is asked to contact Barnet CID on 0208 733 4510, police on 101 or Tweet @MetCC.
Information can also be reported anonymously to Crimestoppers on 0800 555 111 or at crimestoppers-uk.org.
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