City Refrigeration boss Lord Haughey branded as "totally unacceptable" the online attacks Barrhead Travel boss Bill Munro, lingerie tycoon Michelle Mone and himself have endured from some independence supporters for publicly backing the Union.
And the Labour Party donor claimed the "abuse" is preventing other senior corporate figures from entering the debate for fear it will damage their businesses.
Lord Haughey said: "My disappointment is the debate hasn't really started for me. And what I have been disappointed in - whether you believe in independence or not - [is that] I think that some of the abuse people have had for coming out on the No side has been totally unacceptable.
"If you see what has happened to Bill Munro at Barrhead Travel, myself, Michelle Mone or anybody in the past who have voiced their opinion in relation to the status quo being the best option... it's been terrible the way that people have had their heads chopped off."
Asked whether he thought other business leaders are scared of showing support for the Union, he said: "Most definitely. [They are] terrified. If you run a business today and said we are all for staying with the Union and suddenly you have got all these people online saying don't travel with that company, don't buy fridges from that company, what are you going to do?
"It's interesting when you hear some of the politicians saying 'I've also had threats'. Nobody is threatening to ruin their business."
Lord Haughey, who argued voters are being "short-changed" by both sides of the debate over the economic ramifications of the poll, challenged Better Together to help supporters overcome those fears. He said: "It would terrible come the 19th of September and the vote didn't go the way you wanted it to go and you thought could have done more.
"Whatever the people of Scotland decide is what they are going to decide, but what we should have is a debate where people are not afraid to say what they feel.
"Certainly people who want to go with the yes vote are not afraid to say it. But I definitely have not seen anybody on that side being attacked the way people who are pro-Union are being attacked."
Yes Scotland hit back and cited the findings of a recent Sunday newspaper survey, which found those planning to vote for independence are more than twice as likely to suffer abuse.
A spokeswoman said: "People on both sides of the debate should always express their opinions in a reasonable and courteous manner and at the start of the campaign we issued robust social media guidelines. It's incumbent on both sides of the referendum to ensure that the debate does Scotland proud and remains respectful of others' opinions."
Lord Haughey was speaking at a Prince's Trust event in Glasgow which addressed how to tackle youth unemployment in the city.
The event, introduced by Glasgow City Council leader Gordon Matheson, heard from a range of young people who have overcome difficult circumstances in their early lives to find work and start businesses.
These include Melissa Currie, who established a hair and beauty salon with help from the trust after ill health had made it difficult to gain experience and gain full-time employment.
Ms Currie joined Glasgow City Council chief executive George Black, Barclay's global wealth and investment managing director Paul Burd, and Lord Haughey on a panel to answer questions such as whether it is more difficult for 16 to 24-year-olds to find a job in Glasgow than in other parts of the country.
The panel was also asked to consider whether Glasgow is a viable place for young entrepreneurs.
Ms Currie said: "Today's event was important because it brought together a wide range of organisations, senior leaders from Glasgow City Council and senior figures from business together with young people to hear their experiences directly and discuss possible solutions to the barriers young people face."