import pandas as pd
df1 = pd.DataFrame({'A': [1, 2, 3], 'B': ['a', 'b', 'c']})
df2 = pd.DataFrame({'C': [100, 200, 300]})
df2.index = pd.MultiIndex.from_arrays(df1.values.T)
print(df2)
Pandas: Use multiple columns of a dataframe as index of another