The Scotland Institute will be launched by Alistair Darling, the former Chancellor who will unveil the Better Together campaign on Monday.
Jackson Carlaw, deputy leader of the Scottish Conservatives will attend the Scotland Institute launch while Liberal Democrat veteran Sir Menzies Campbell has been invited to join the board.
It is a guest list suggesting cross-party support from the pro-Union parties, mirroring Better Together.
Blair McDougall, campaign manager of Better Together, the official group running the No campaign, welcomed the arrival of the think-tank but stressed: "It's not our vehicle, we are not owners of it, but it's helpful to the cause."
But the founder of the Scotland Institute, hedge fund millionaire Azeem Ibrahim, last night denied that the absence of the SNP or Greens from the launch was an indication of an anti-Independence stance.
He said: "It is a completely independent think tank. Both sides have failed to articulate evidenced arguments, therefore we need clear, sound work looking at all the options."
On the invitation to Mr Darling to launch the event, he said: "I don't know anything about the Better Together campaign. I simply asked him as a distinguished former Chancellor."