The Brazilian's dream move to the Camp Nou in January 2018 quickly turned into a nightmare and he's struggled to settle into the team since.
He was palmed off to Bayern Munich on loan in the 2019/20 season and are understood to have tried to sell him on more than one occasion. But no one will take him.
Arsenal are the latest club Barcelona are trying to get Coutinho to join, reportedly using him as a makeweight in their attempts to sign striker Pierre-Emerick Aubameyang.
The two clubs have done plenty of business together in the past. Thierry Henry, Cesc Fabregas and Thomas Vermaelen are just a few players to have left north London for Catalonia.
The Barcelona-Arsenal dealings haven't been totally one-sided though. The Gunners managed to get forward Alexis Sanchez for a cool £35million in the summer of 2014.
Liverpool appeared to be the more likely destination for the Chilean, especially with Barcelona signing Luis Suarez in the same summer.
However, then-Reds boss Brendan Rodgers explained that Sanchez had his heart set on a London move.
"He's a fantastic player and would have suited us," Brendan Rodgers said in 2014.
"That was one where geography dictated where he wanted to go, simple as that. It wasn't due to a lack of ambition by the club, it was about where the player and his family wanted to live."
But former Gunners sporting director Dick Law remembers it differently, insisting the clincher was the fact Sanchez wasn't a makeweight in any deal involving Arsenal, plus a personal plea from Arsene Wenger very much helped.
"It all started with [former chief scout] Steve Rowley at the Toulon tournament," Law told Goal.
"Sebastian Rozental, who works for the agency Twenty Two which is owned by Sanchez's agent Fernando Felicevich in Chile, walked over and said to Steve: 'Sanchez is going to leave Barcelona'.
"All of us being natural sceptics, we thought there was no chance when Steve called us. So we went back to the agents and they said it was true and that Barcelona had even given them a price.
"So I flew out immediately to [Chile capital] Santiago to just get a sense from Fernando about how serious this was. If we were just going to be a stalking horse for Juventus or Liverpool who knew that they were losing Suarez, then we didn't want to play that game.
"Off the back of that meeting I made the judgement that there was half a chance, but the closer on the deal was Arsene - he won that one for us.
"Arsene met with Fernando in Rio at the World Cup two or three times over the next ten days talking about his philosophy, about where Sanchez could play, that sort of thing. Off the back of those conversations, Sanchez really took a liking to the notion of coming to London.
"Liverpool were throwing a tonne of money at him, but my understanding was that there was no real personal contact. My conclusion was that Sanchez felt like a makeweight in the Liverpool - Barcelona transfer negotiations for Suarez.
"It was more of a money deal than anything else and I think when you deal with South Americans, you have to throw a human element in there."
Arsenal fans were glad Wenger went the extra mile to sign Sanchez, who was fantastic in his three-and-a-half years at the club. Widely thought of as one of the most talented players of the Emirates era, he helped them win two FA Cups and also won Arsenal's player of the season award twice.
He left to join Manchester United in January 2018 with Henrikh Mkhitaryan going the other way and Sanchez's career really stalled in his time at Old Trafford. He later revealed that he wanted to go back to Arsenal after just ONE training session at Man United.
Sanchez is now in a similar situation to Coutinho in trying to rebuild his career. The 32-year-old is currently at Inter but struggled to establish himself in the first-team during their title-winning campaign last term.
In this sense, Arsenal know what it's like to be in Liverpool's situation as the reports very much suggest Coutinho is the makeweight in the deal.
The demand for Sanchez seven years ago was a lot higher than the demand that's there for Coutinho now, however.