Pandas Outer merge

[skollu826]

I have two data frames
dataframe 1
col1 col2
1 A
1 B
2 C
5 Z
4 Q

dataframe 2

col1 col2
1 A
1 B
2 E
3 X
4 R
4 S
I am performing an outer merge

merge = pd.merge(dataframe1, datagrame2, on="col1", how='outer')
I get

col1 col2_x col2_y
1 A A
1 A B
1 B A
1 B B
2 C E
5 Z NAN
3 NAN X
4 Q R
4 Q S

How do I get the output as below

col1 col2_x col2_y
1 A A
1 B B
2 C E
5 Z NAN
3 NAN X
4 Q R
4 Q S
Any help will be appreciated. Thank you