The Liberal Democrats will "act as the guarantors" of more powers for Scotland if it rejects independence, according to the Deputy Prime Minister.
But any final settlement would have to be negotiated with the other pro-UK parties, businesses, civic Scotland and the SNP if they are willing to embrace devolution, Nick Clegg will say in a speech in Edinburgh today.
Lib Dems want Holyrood to raise half of its own revenue and set its own rates of income tax, capital gains tax and inheritance tax.
But Mr Clegg, the party's UK leader, said their proposals "are not the final word", with Labour's offering already on the table and the Conservatives due to publish their own devolution proposals in the next few weeks.
"The story of devolution - the journey to home rule - is not yet complete," Mr Clegg will say in a speech in Edinburgh hosted by the Scottish Chambers of Commerce.
"We believe we can empower the Scottish Parliament and strengthen its accountability even further.
"In the event of a No vote this September, all three pro-UK parties have pledged to deliver more powers.
"The Prime Minister has started to talk about the Conservatives' proposals. Labour published theirs some months back. And the Liberal Democrats put our plan out there more than eighteen months ago.
"All three parties are clear in their commitment. More powers will come."
He will add: "We want to see a more powerful Scottish Parliament, whose actions are more accountable to the people who elect it.
"That means raising more of the money it spends on the priorities that it has chosen.
"The 2012 Scotland Act will mean that from 2016 the Scottish Parliament will raise about 30% of the money it spends.
"Under our proposals we raise that level up to over 50%.
"Income tax paid on earnings by Scottish taxpayers should be the responsibility of the Scottish Parliament.
"With the rates and bands determined here in Scotland. So should capital gains tax. And inheritance tax too.
"Why should these be the reserve of the UK Parliament only?
"If people in Scotland want to further cut the income tax burden on middle-income earners, that should be a choice for them.
"If they want to raise it in order to take less from lower earners, again they should be free to do so.
"If they elect a Parliament whose wish is to cut or increase capital gains tax, inheritance tax, or spending on schools and hospitals - well, so be it.
He will continue: "Of course, our proposals are not the final word.
"The settlement on further powers will need to be negotiated. Between the three pro-UK parties of course.
"With the SNP, if - for the first time - they were willing to be part of the devolution conversation too.
"But also with those outside politics who have a major stake to claim in Scotland's future.
"Business must be at that table - contributing to this work, influencing its outcome, getting it right.
"That's why I hope you vote No in September. It's the positive choice for our positive future together."
SNP MSP Annabelle Ewing said: "Given that Mr Clegg's party have been promising Home Rule for over a hundred years, people in Scotland are unlikely to view them as the guarantors of anything - except continued Conservative rule from Westminster.
"Let's not forget that, as recently as 2011 the Lib Dems had the chance to beef up the Scotland Bill with a raft of new economic powers that they had previously supported - but they reneged on their previous commitments.
"With such a track record, it is little wonder that the Lib Dems are currently fighting it out for sixth place in the European elections in Scotland.
"Scotland is an immensely wealthy country, richer per head than the UK, France, Italy and Japan - but only a Yes vote in September is the only way to guarantee that Scotland gets the vital job-creating powers it needs to build a fairer, more prosperous society."