The big-spending Edinburgh club have made Mehdi Taouil their fourth signing of the close season but Diamond’s proposed move has collapsed.
Diamond was not offered a new deal at Pittodrie after the centre back made it clear he wished to move on.
Dons boss Craig Brown confirmed there is no way back to Pittodrie for Diamond, saying: “Zander won’t be coming back to Aberdeen.”
It is an ignominious end to what was once a hugely promising Dons career for Diamond.
The defender shone in Aberdeen's Under-19s, earning him a regular first-team berth while still in his teens.
His full-on, fearless style quickly made him a fans' favourite, but this started to turn sour in the last couple of years of his time at AFC.
Photographs of Diamond in Celtic gear with a Celtic cake circulated the internet following a birthday celebration angered a section of the Reds' support.
And Dons fans who turned a blind eye to that were less able to forgive an appalling loss of form under Mark McGhee's management at a time when defensive leadership was sorely required.
Now Diamond's agent has a job on finding his client a reasonable level of club to play for this summer.