Boku no Ushiro ni Majo ga Iru(2008)

Boku no Ushiro ni Majo ga Iru

When Ryuusuke Nanri changes schools after his parents' divorce, he is made to sit in front of a strange girl called Miya Fujimoto. Miya always wears Gothic Lolita-like fashion, carries a strange book and her cat Judah around with her and claims to be a witch. From now on, Ryuusuke will become the main target for all her strange witch experiments...

(Source: MangaHelpers)