The legendary Bulgaria striker took charge of the struggling side in a bid to steer them towards European qualification, but has admitted to losing patience with the club's hierarchy, claiming he has not enjoyed the support he expected when taking up the post.
In a letter intended for the local media, the former Barcelona star stated: “I’m fed up, I’m leaving.
“I agreed to start coaching without a contract and I had a great desire to help.
"I had the support of the players and my staff. We endured until it became clear there's no chance of promises being fulfilled.
"It is not my understanding of fair, transparent and professional work. This is no way to achieve high goals if there's no respect between players, coaches and officials on the one hand, and the club owners on the other."The 31-time Bulgarian champions have been plagued by financial problems in recent seasons, and could only manage a third-placed finish last season.
The club face having to play in an amateur championship next season unless they are able to merge with another top-flight side before the league commences on July 20. Fifteen supporters were arrested last month for vandalising the Bulgarian FA headquarters after the governing body declined to sanction any such merger.
Stoichkov, who won seven trophies with the club during his illustrious playing career, became the club's fourth coach this year, and their ninth since January 2010.