The Bundesliga giants have beaten the Reds to the signing of the Armenia international who leaves Shakhtar Donetsk for Germany on a four-year deal for a fee of €27.5 million
The German side confirmed on Monday that they had agreed terms with Shakhtar and the 24-year-old has now signed a contract until the summer of 2017 with his new club.
Goal understands Liverpool had been in the hunt for Mkhitaryan but fell behind to Dortmund after the Champions League runners-up made a concerted effort to sign the Armenia international.
Dortmund, meanwhile, see Mkhitaryan as the perfect replacement for Mario Gotze who moved to Bayern Munich earlier this summer.
"We are very pleased to have strengthened our attacking midfield with a superb signing like Henrik Mkhitaryan," sporting director Michael Zorc told the club's offical website.
BVB CEO Hans-Joachim Watzke was equally satisfied with the arrival of Mkhitaryan, but admitted that signing the Armenia star was not an easy task.
"This was not an easy transfer, but we were determined to get our man - and now we have him," stated Watzke.
The attacking midfielder is BVB's third signing of the summer transfer window after the previous capture of Sokratis from Werder Bremen and Pierre-Emerick Aubameyang from Saint-Etienne.
Mkhitaryan will wear the No.10 jersey at Borussia.