From Shoujo-Sense:

While working as a monitor in the all-but-abandoned school library, first year Mei finds herself captivated by a mysterious boy with hair the colour of the setting sun. Never expecting to see him again, she's surprised when he shows up the next day, only to fall asleep and end up rushing out of the library suddenly and without a word... Who is he, and where does he go at the same time each day?

From Mystic Iris:

For Mizuki, her life turned for the worst when her long-time neighbor and tormentor Ryohei joined her high school as a student teacher. Now she can't seem to catch a break from him in school nor at home! What can she do now that this sadist keeps leading her around, making her day to day life a living hell?!