Drama Special Series Season 2: Ordinary Love (2012)

Both dramas have Yeon Woo Jin playing a male lead trying to find the truth about his brother's death and intentionally approaching the female lead who is somehow to connected to it without letting her know who he really is. Also, they fall in love.

Having Yeo Woo Jin as a lead made me remember about Ordinary Love, where I first encounter Woo Jin's appearance. Somehow, episodes 14-15 of Introverted Boss was similar to entire story of Ordinary Love. Falling in love with someone you can't be together due to family issues..

It's not exactly the same plot of course but it's similar