The idea, it has emerged, was floated in a pitch to the No side, Better Together, by an advertising agency.
But Yes Scotland has already stolen a march by printing 750,000 postcards describing itself as "the real KNOW campaign". The dispute about slogans emerged after documents detailing how the agency wanted to market Better Together were leaked to rivals at Yes Scotland.
A Better Together spokesman admitted that the organisation was taken with the "know" campaign idea. "We liked that bit," he said.
But the organisation is not going ahead with the planned campaign. "It was a pitch to us by an ad agency for a potential campaign," he said. "We didn't go ahead with it."
The advertising executives also suggested the campaign try to avoid one of its central messages, the word "No". In a section of the leaked document they warn that the public might think "Saying No = saying No to Scotland". Some voting experts believe it is more difficult to be the "No" side in a referendum, as voters can respond negatively to the message.
It is not the first time the words used to describe Better Together have seen the organisation make headlines. Earlier this year the pro-Union campaign came under attack after it emerged insiders had dubbed it "project Fear".
Last night the SNP hit out at the No campaign, saying it could change its wrapping but not its content. SNP MSP Stuart McMillan said: "The fact that they are clearly contemplating a relaunch is a sign they must be worried."
Blair Jenkins, chief executive of Yes Scotland, said: "The No camp must know they are stuck in a negative campaign, which is also a deeply cynical one, and nothing it appears they're proposing to do changes that."
Meanwhile, medical charities have warned millions of pounds of research funding could be put at risk by independence.
The Association of Medical Research Charities also warned a Yes vote could make medical trials across the UK more difficult to carry out.
Labour MSP Dr Richard Simpson, a GP and a Fellow of the Royal College of General Practitioners, said: "The only thing putting this at risk is Alex Salmond's obsession with independence. Last month's White Paper failed to provide any credible answers about the consequences of separation for Scottish medical research and medical schools."