Abstract: TMTTF (tetramethyltetrathiafulvalene) and TMTSF (tetramethyltetraselenafulvalene) based organic charge transfer salts are representatives of highly correlated quasi-1D electron systems which exhibit rich variety of ground states that can be easily tuned by pressure. They have been the top interests among researchers for the past few decades. Some concepts, such as the interplay between the magnetism and superconductivity, are believed to hold the key to the understanding of the mechanism of the high T_c superconductivity. How the repulsive Coulomb interactions U and V control the phases in these systems and how they evolve with pressure, become the major concern of numerous theories and experiments. Here we present the NMR and EPR studies on two compounds of this family, namely, (TMTTF) ₂SbF₆ and (TMTSF)₂ClO₄. The 121Sb and 19F NMR measurements reveal that at ambient pressure, the anion SbF₆ will align along a preferred orientation below a crossover temperature, T ∼ 120 K. This unique property of the anion adds an additional degree of freedom to the system. The pressure studies of the (TMTTF)₂SbF ₆ show that this compound should be positioned in the lower pressure regime of the generic phase diagram. At ambient pressure, the charge ordering (CO) state at higher temperatures suppresses the spin-Peierls (SP) instabilities and an antiferromagnetic (AF) ground state is realized at low temperatures. Both the CO and the AF states are found to be suppressed by pressure very quickly and the ground states under intermediate and higher pressures are determined by how much disorder is introduced into the system. For the more disordered samples, the ground states resemble the familiar sequence of AF→SP→AF while for the more relaxed samples, no long range order is observed down to 1.8K. This is refreshing since a lot of the properties in this particular state are very similar to those observed in K-(BEDT-TTF) ₂Cu₂(CN)₃, which is believed to have a spin liquid ground state. Interestingly enough, this shows the anions are participating in a certain way in the formation of different electronic ground states. The compound (TMTSF)₂ClO₄ shows another example of how the electronic state can be controlled by the lattice potential. The ordering of the perchlorate anions results in a unit cell doubling hence two bands crossing at the Fermi level. The NMR measurements show that the fluctuation in anion orientations directly controls the spin density distributions between the stacks.