The Master's Sun (2013)

Both dramas include Ghosts
It also includes the Female leads being able to see and to communicate with Ghosts.

the leads in both can see ghosts and ghosts follow them around to relieve their grievances.

it's not excatly the same plot but in both series the female lead is able to see ghosts.
if you liked Ghost friends I highly recommend watching the master's sun

Native Title: ??? ??
Also Known As: The Sun of My Master , The Sun Of The Lord , Master's Sun , Joogoonui Taeyang , Jugunui Taeyang
Screenwriter: Hong Jung Eun, Hong Mi Ran
Director: Jin Hyeok
Genres: Horror, Comedy, Romance, Supernatural
Tags: Ghost, Eccentric Female Lead, Ghost-seeing Female Lead, Rich Male Lead, Clingy Female Lead, Successful Male Lead, Trauma, Secondary Couple, Eccentric Male Lead, Hidden Identity

If you want more thriller (but not ghosts, unfortunately) Healer has it too...

Also balanced with bickering romance... Just check it out... Highly recommended!!

Both have quirky bosses falling in love with their subordinates. Fox's Summer is a fluffier and funny series, with a sassy and feisty lead girl. No paranormal or fantasy storyline in FS.

Both has a supernatural element to it. In Goblin, Eun Tak can call him by blowing a candle. In Master's Sun, Tae Gong Shil can avoid ghosts by touching him.

While very different in plot, both dramas have a ghost-seeing FL and a "unique" ML (he can chase her ghosts away vs. he can help her because he isn't human). Both have horror elements and a slow-burn romance.

They both have ghosts with unresolved problems stopping them going onto the afterlife which are dealt with by the main characters.

Both female heroine can see ghosts
Although Black is truly a serious crime-drama-fantasy, The Master's Sun is more light-hearted, romantic drama
Both dramas are worth watching!!

Both are my two favorite romantic comedies of all time with amazing acting, OSTs and love stories. Both are very touching heartwarming love stories about male leads with PTSD who push others away due to their fears of getting hurt again. In Woo Jin's case from 30b17 he thinks it's that he's afraid of hurting others again, but both are very mistaken about their traumatic incidents which the female leads help them to realize. Both female leads in their own ways haven't been able to live up to their brilliant younger selves due to life altering accidents and both shows are about how both couples help each other find the courage to live and love again. Shin Hye Sun is in my top 5 favorite actresses right up there with Gong Hyo Jin though Shin Hye Sun has only recently started getting leading roles. They are both so lovable as people and so talented as actresses. They both make me cry buckets of tears and laugh ridiculously loud and feel amazed by their talents both comedically and emotionally. They both become their characters so seamlessly that I can't wait to watch their next shows.

In both dramas one lead has a serious problem that goes away if they are together with the other lead and that's why they keep them close.