SMG, which owns Scottish Television, has broken off merger talks with UTV and appointed a new chief executive.
SMG was considering the Ulster TV offer
Negotiations wavered because of differences over the level of SMG's pension liabilities, according to SMG.
The Glasgow-based group named Rob Woodward, who was commercial director of Channel 4, as its chief executive.
A deal would have created a media group worth about £400m after Ulster TV, which operates TalkSport, opened talks with SMG last year.
Richard Findlay, the former boss of Scottish Radio Holdings, is to be the SMG chairman instead of Chris Masters.
Five other SMG board directors - David Dunn, Steve Maine, Martyn Smith, MT Rainey and Tim Gardam - have resigned with immediate effect.
A statement from SMG said that the new board structure had received overwhelming support from leading institutional shareholders.
Richard Findlay, chairman of SMG plc, said: "I am delighted to have been appointed to take the company into a new period of transition and development.
"I will be working closely with our new team, led by Rob Woodward, to implement a strategy to deliver value to our shareholders."
Rob Woodward, chief executive of SMG, said: "I've observed the business closely for some time and am delighted to have the opportunity to revive its fortunes.
"This business displays some unique assets, along with a wealth of creative talent. I very much look forward to unlocking its future potential, serving its audiences and participating fully in the digital world."
Investor Hanover Investors Management holds a 12.6% stake in SMG.
Matthew Peacock, principal of Hanover Investors, said that he believed that the business had been fundamentally undervalued and had a promising independent future under the right leadership.
He added: "I would like to thank Chris Masters and his colleagues for their co-operation during our recent discussions and wish them every future success."