If you're looking for anime similar to Chuunibyou Demo Koi ga Shitai! Ren, you might like these titles. All recommendations are made by Anime-Planet users like you!
Third-year student and guitarist Haruki Kitahara wants nothing more than his Light Music Club to play at his upcoming, final school festival. But soon, the other members quit, and Haruki resigns himself to playing one last solo jam session in the now-empty practice room. As he strums the chords of his favorite song "White Album", Setsuna, the school idol with an amazing voice, and Touma, an extraordinarily talented pianist, suddenly join the performance from an adjacent classroom and atop the roof, and Haruki becomes determined to keep the club going. Though one of the girls would rather avoid the spotlight and the other is a loner, Haruki’s passion wins them over and they agree to join. Now, with the performance date fast approaching, the trio spends all of their time together practicing, learning the joys of friendship, and the heartache that comes from falling in love with the same person...
I have also made a recommendation between Aura and the first series of Chuunibyou and the reasons for this recommendation is pretty much the same, the story between the two are quite similar in both storyline and characters. A delusional girl meets a boy who is trying to get away form his awkward past, then the boy gets involves and goes back to his delusional self from some time before and then helps the girl sort of story. The second series of chuunibyou is very similar to the first so this recommendation is pretty much the same, same reasons and explanations. So I say if you enjoyed the chuunibyou story then Aura is a good watch for you and vise versa.