Giovanni di Stefano has called upon the Marr brothers to follow his example and resign from the board of Dundee.
Di Stefano had offered to invest £26m in Dundee
The controversial lawyer has stepped down ahead of the debt-stricken club's annual general meeting, scheduled for 15 February.
Dundee, who went into administration in November with debts of around £20m, have also lost the services of commercial manager Jim Connor.
Meanwhile, administrator Tom Burton is talking with a consortium of Lithuanian businessmen with a view to buying the club.
The Lithuanians want to use Dens Park to showcase talent from the Baltic state.
Di Stefano appeared as a self-titled saviour of Dundee in August and offered to invest £26m to save the club but his position as a director was never ratified by the Scottish Football Association.
The Anglo-Italian businessman helped bring in big-name players Craig Burley and Fabrizio Ravanelli, but they, along with 13 other players, were sacked by the club when they were placed in administration.
At the end of December, he offered to buy Dens Park, while he also announced that he had formed Dundee City Football Club Ltd to take the place of Dundee should they become extinct.
Di Stefano has now called on club owner and chief executive Peter Marr and his brother Jimmy, the chairman, to step down so new owners can move in.
"I call upon both Peter and James Marr to resign and to assume the liabilities incurred by their management into their own private companies," said Di Stefano.
"And allow the club to survive under the management of whoever seeks to advance football at Dundee.
"It has been stated by both Peter and James Marr that my remaining on the board of directors precluded the club from obtaining short, medium and long-term finance. I have no doubt such is not the case.
"Nevertheless, no opportunity must be waived in the quest for the club to survive. We shall now indeed see if any other investors truly do come forward."
45-year-old Connor, who joined the club in 1996, is to join accountancy firm Avantis Sports Solutions.