The Serbia international has spent the last three seasons at Bremen after two campaigns on loan at 1860 Munich from OFK Beograd, but has agreed a deal to move to Frankfurt at the end of the current campaign.
Ignjovski has made 12 Bundesliga appearances for Bremen so far this year, and Frankfurt sporting director Bruno Huebner was delighted with his capture.
"We are very happy that the transfer has gone through," he said.
"At 23, Aleksandar has already considerable experience and can be deployed in several positions.
"He can play in the defensive midfield or as a full-back."
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.