High-yield syntheses of dilithio-derivatives of furan, thiophen, N-methylpyrrole, 3-methylfuran, and 3-methylthiophen. Application of the method to 2-methylfuran, 2-methylthiophen, 2,5-dimethylfuran, 2,5-dimethylthiophen, benzobfuran, benzobthiophen, pyrrole, and indole