The phase diagram of the quasi-one-dimensional model which is most relevant
to organic ferromagnets of a certain kind is considered. In this model, st
rong electron-phonon interaction is considered adiabatically and the coupli
ng between local spins and pi -electrons is treated within a mean-field the
ory. A full phase diagram is given. The results show that there are two new
kinds of phase which were not revealed in previous treatments. Our results
may be helpful for the synthesis of organic ferromagnets.