Protect the Boss (2011)

Same writer and director. Plus the stories have simmiliar cute and light feeling with main guys chasing after female leads.

Some may disagree since the situational set-up is not the same (ie in Marriage, Not Dating they are not in a boss/employee relationship but a contract marriage relationship) but I see very strong similarities between the FL and ML interactions.. The ladies are both straight up FEISTY: physically feisty and argumentatively feisty and determined-to-be-themselves-when-they-don't-necessarily-feel-accepted-by-society feisty. In both dramas, the MLs are equally assertive and give back as good as they receive and you can tell they subconsciously like the challenge the FL puts up as they find themselves falling for the girl against their wishes. The banter is right up your Beatrice&Benedict alley (my favorite type of romance to watch).

boss & secretary relationship that begins with lots of fight and bickering and end up being lovey-dovey couple

The leading lady is a strong person, the leading man get psychological treatment and the leading lady also helps him. The Drama is very funny. The main actor becomes to played from Ji Sung.

Both shows have a neat freak and germaphobic boss however the differences are big in Protect The Boss the lead girl is a tomboy and loves to fight they don't really live together while in Just You the lead girl is a sweet girl who loves her flowers but what both shows carry in common is boss and employee falling in love.

Dokko Jin and Cha Ji Heon are very similar characters and both dramas are very funny.

In both have story about boss and coworker,also contains more than one love stories and strong female lead falls in love with more childish guy.