for col2 in df2.columns:
    for col1 in df1.columns:
        cond = df2[col2].isin(df1[col1]).all()
if cond:
    d[col2] = col1
print(d)
{'MemberIdentifier': 'EmployeeID', 'DateofBirth': 'DOB', 'YOW': 'Age'}
Match Data of 2 Excel Sheets where Column Names are Different