However, the 28-year-old's move likely depends on Dortmund securing a replacement, thought to be Belgian worldwide Michy Batshuayi from champions Chelsea, and the latter getting French veteran Olivier Giroud from the Gunners.
Olivier Giroud, one of the best backup strikers in the Premier League, has reportedly arrived at Chelsea.
Arsenal, however, were awaiting their club record signing from the German side before relinquishing the France worldwide.
Arsenal waited a long time to get Aubameyang over the line but they did just that on Wednesday by smashing the record fee they paid for Alexandre Lacazette in the previous window.
In total, Aubameyang scored 98 goals in 144 games for Dortmund in the German league after joining from Saint-Etienne in 2013 and was the top scorer last season with 31.
The former Montpellier ace scored 105 goals in 253 outings for the north Londoners and won the 2017 FIFA Puskas Award for his scorpion-kick goal against Crystal Palace on New Year's Day.
Arsenal boss Arsene Wenger - who last August kept the football world on tenterhooks as he held out selling Alexis Sanchez to Manchester City because he failed to secure Thomas Lemar from Monaco - did not wait until the last minute to land the Gabon striker.
The fee for Aubameyang was identical to that paid by Manchester City for France under-21 global Aymeric Laporte on Tuesday.
The French forward signed with the Gunners in 2012.
The 25-year-old attacking midfielder was Tottenham's only signing of the January transfer window and joined for a fee of 25 million pounds ($35 million) on a contract that runs until 2023.
It means Arsenal are going to have a lot of games to negotiate, starting with next month's round-of-32 tie against Ostersunds.