  Using a combination of Density Functional Theory, mean-field analysis and
exact diagonalization calculations we reveal the emergence of a dimerized
charge ordered state in TMTTF$_2$-PF$_6$ organic crystal. The interplay between
charge and spin order leads to a rich phase diagram. Coexistence of charge
ordering with a structural dimerization results in a ferroelectric phase, which
has been observed experimentally. The tendency to the dimerization is
magnetically driven revealing TMTTF$_2$-PF$_6$ as a multiferroic material.
