Alex Salmond has indicated that the SNP could seek to form a minority administration.
With the Scottish Liberal Democrats ruling out a coalition deal unless the nationalists drop their commitment to an independence referendum, the SNP and Scottish Greens are likely to form an alliance.
The SNP and Greens combined would have 49 seats, still well short of a majority in the Scottish Parliament.
But Salmond indicated that prospect could be "exciting".
"You wouldn't be able to ram things through as the government does at Westminster," he told the BBC's Today programme.
"I've already stated that my preference in this situation is to have and build a coalition. There are certain advantages in that.
"But would it be an entirely bad thing if a government had to concentrate on areas where it could build a consensus in a parliament?
"Not an entirely bad thing. It would be an unusual situation and, I suppose, quite an exciting situation."
SNP deputy leader Nicola Sturgeon, meanwhile, has called on the Lib Dems to return to the negotiating table.
"We hope to make progress today with the Greens, to bring them into this progressive coalition that we want to build," she said.
"And we would hope that the Liberal Democrats would agree to get round the table."
She added: "It's only possible to explore the compromises if you are talking to each other around the table so our invitation to the Liberal Democrats to get round the table and talk to us is still very much on the table."
Dods Parliamentary Communications Ltd