The alliance, which will target enterprises at the pre-revenue stage, aims to provide funding worth several hundreds of thousands of pounds to new companies in its first year.
The organisations will combine their knowledge, leads and investor bases to provide alternative funding at a time when banks and building societies continue to face criticism for not doing enough to support new businesses.
The partnership effectively offers start-ups the opportunity to attract funding from two sources, with Gabriel investors potentially matching the sum targeted on Squareknot. Gabriel was founded in 2012 by Gillian MacAulay, managing director of the Strathclyde University Incubator, and is focused on start-ups in the technology sector.
So far, its 15 investors have provided £160,000 to fund Scottish businesses, and raised a further £70,000 in grants, loans and other funding. It completed its seventh deal in December and hopes to have between 20 and 25 members by the end of the year.
Squareknot was billed as Scotland's first ever equity, loan and reward crowdfunding platform when it was launched by Derek Bond and other Scottish entrepreneurs last year. It recently completed an £80,000 funding campaign for Darlington Football Club and currently has a campaign for East Fife FC to raise £25,000 for stadium improvement. So far £21,700 has been pledged.
Talks over the collaboration began when Mr Bond joined Gabriel as an investor, shortly after he set up Squareknot.
A test case has still to be established, but Ms MacAulay hopes to put a joint investment opportunity to Gabriel investors at their next meeting in April.
She said: "It's about joining forces and collaborating with people.
"Derek and I both want to see early stage businesses get off the ground and get running. That is the most important part.
"If we can join forces and make that happen a bit quicker, with perhaps a bit more money, then great."
Mr Bond, who established Squareknot with Brian Smillie senior and Brian Smillie junior, said: "I am delighted that we are going to take advantage of the synergies between Squareknot and Gabriel Investments.
"Early stage businesses requiring seed funding will be able to benefit from the advice and support that the Gabriel business angels can bring, as well as the additional funding that can be raised by Squareknot through a supplementary crowd of investors.
"As the first formal affiliation in Scotland between a business angel syndicate and crowdfunding platform, we hope to pave the way for further collaboration between the business angel community and the revolutionary concept of crowdfunding."