In [6]:

import pandas as pd
a = 'string1'
b = 'string2'

test_dict = {'col1':{a:type(a), b:type(b)},'col2':{a:type(a), b:type(b)}}
df = pd.DataFrame(test_dict)
html = df._repr_html_()
print html
df

<div style="max-height:1000px;max-width:1500px;overflow:auto;">
<table border="1" class="dataframe">
  <thead>
    <tr style="text-align: right;">
      <th></th>
      <th>col1</th>
      <th>col2</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><strong>string1</strong></td>
      <td> <type 'str'></td>
      <td> <type 'str'></td>
    </tr>
    <tr>
      <td><strong>string2</strong></td>
      <td> <type 'str'></td>
      <td> <type 'str'></td>
    </tr>
  </tbody>
</table>
</div>

Out[6]:

	col1	col2
string1
string2