N.m.r. spectral studies demonstrated that Meisenheimer salts were formed by addition of alkali metal methoxides to 4-cyano-2,6-dinitroanisole, 4-methoxy-3,5-dinitropyridine, and 2,6-dinitroanisole, but not with 2-methoxypyrimidine. Crystalline salts were isolated after addition of methoxide to the cyanodinitroanisole and methoxydinitropyridine. The stabilities of the Meisenheimer salts were found to be heavily dependent on the ability of ring substituents to accept negative charge.