His performances during a single season at Signal Iduna Park - six goals in 32 appearances - convinced then Blaugrana president Josep Maria Bartomeu that the Frenchman would be the ideal replacement for Neymar.
Of course, Philippe Coutinho was also expected to fill the boots of his compatriot, but it was Dembele who was more keenly anticipated by the Blaugrana faithful.
Ousmane Dembele's talent and disciplinary problems
Dembele's key is was his pace and, more importantly, ability to dribble at pace and create chances for the forward inside the box. He made 15 assists across all competitions for Borussia Dortmund. This is when the rest of the world really began to take notice of him.
What made Dembele unique was his nimbleness on the ball and decision-making, attributes highly prized by the Blaugrana since the days of Johan Cruyff. Dembele was not a player ingrained in 'the Barcelona way', but it was believed he could be moulded into one. After all, he was only 20 at the time of his arrival.
A perennial problem with wealthy young players, however, has been their penchant for lack of self-control. Dembele's time in the last five years at the Camp Nou has been anything but smooth by any stretch of imagination. He has been inconsistent, plagued by injuries on more than ten occasions and has been an aloof individualist rather than a team player.
Ousmane Dembele's improvement in 2021-22 season and contract fiasco
The 2018 FIFA World Cup winner's idiosyncrasies have been a constant source of headache for Barcelona in the last half a decade.
However, last season, the situation seemed to change dramatically. After his appointment as the manager late last year, Xavi Hernandez had made it clear that Ousmane Dembele would be a massive part of his plans.
Indeed, Xavi almost bent over backwards in his praise of the Frenchman in an attempt to make the latter feel more valued in the squad. Xavi's strategy worked perfectly. Dembele produced his best performances in a Barcelona shirt during the 2021-22 season.
He provided 13 assists in 32 games, although he scored just twice across competitions. Nevertheless, he looked happier and more involved in the squad. The Frenchman was also largely injury-free and played with more intelligence.
However, Dembele is now a free agent after failing to agree a contract extension with his club. He's not the first player to be misguided by his agent, and he will not be the last either. Legendary Manchester United manager Sir Alex Ferguson famously hated all agents, and his dislike for certain agents is well known.
Dembele's agent Moussa Sissoko has been a negative influence on the player primarily because of his high wage demands. Xavi has reiterated his love for Dembele and has requested the club to do everything in their power to keep him tied to the Camp Nou. Dembele has also expressed his desire to remain, but the two parties cannot come to a financial agreement.
This fiasco is nothing new, but now it has the risk of it becoming a potential embarrassment for Barcelona. Laporta and his men have been uncharacteristically patient with Dembele. Wonder if the presidents of other top clubs would be so accommodating to a player who is teetering to sign a contract extension with them.
One should be in no doubt that Dembele's agent Sissoko has had a big role in the player's current contractual situation. It all comes down to commissioning money and the ability to leverage the best possible package out of this tricky situation. Dembele's wage demands of up to €480,000 excluding other perks seem astronomical to the club who are already walking a financial tightrope.
What's next for Ousmane Dembele?
Once again, greed and ingratitude seem to overshadow a player of great quality. Dembele simply does not seems to appreciate how patient Barcelona have been with him as he laid like a patient on hospital beds. The situation has become so ridiculous that Dembele now signing any type of contract would be like an insult to the Blaugrana. They have simply been too respectful of the Frenchman.
When one looks back on the career of Dembele a decade from now, one would see a pattern emerging from the outset. That of a player who has been more trouble than he's worth, and even his best performances for Barcelona – which have been few and far between – cannot justify his attitude.
As things stand, Dembele is now a free agent available for other clubs to sign on a Bosman deal. If Barcelona do sign him now, he'll be categorised as a new signing with more complications along the way.
Ousmane Dembele has also been offered a contract by Chelsea, but it's nowhere near what the Frenchman wants. It seems nobody can pay Dembele the money he thinks he deserves as there seems to be no end in sight to this fiasco
Dembele’s greed and ingratitude have soured his otherwise considerable footballing talents. It remains to be seen where his next destination lies.