You can do this using the parameter regex=True:
In [37]: s.replace(d, regex=True)
Out[37]:
0 aBc
1 aBe
2 aBg
dtype: object
As you already learned , this is a replacement for RegEx, and it wonβt work as you expected:
In [36]: s.replace(d)
Out[36]:
0 abc
1 abe
2 abg
dtype: object
works as expected:
In [38]: s.replace({'abc':'ABC'})
Out[38]:
0 ABC
1 abe
2 abg
dtype: object