Police say the men demanded the money at Mr Mullens' luxury car dealership on Parramatta Road at Burwood, in Sydney's inner west, about 3:30pm (AEST) yesterday.
But within 10 minutes police arrived, including officers from the gangs squad, and arrested them.
Police say the men, aged between 24 and 30, have bikie gang links.
They have been charged with demanding property with menaces and participating in a criminal group, and held in custody to face court today.
Mr Mullens' car dealership was also the target of an armed robbery last Thursday afternoon.
Police say a group of masked men took four luxury cars during the raid.
But the cars were found parked outside the dealership in pristine condition the next day.