The existing 8,000 square foot retail unit on the site will be refurbished and the new student halls completed in time for the 2016/17 academic year.
The deal is the third development to be funded by a share pacing by Unite last Summer.
The other sites are in Aberdeen and Newcastle with a fourth location set to be announced shortly.
Richard Simpson,Managing Director of Property for Unite said: “We are delighted to announce the acquisition of this new site in the Scottish capital, presenting a rare chance to develop student accommodation in a prime central location.
“There are 41,000 full time students seeking accommodation in Edinburgh with only 12,500 corporate and university bed spaces available.
“This structural shortage and the strong central location of this site mean the property is well located for University of Edinburgh students and will also appeal to students from other Edinburgh institutions such as Napier University, Herriot Watt University and Queen Margaret University.
“This development will add to our existing portfolio of five properties in Edinburgh, where we currently provide a home for 717 students.”