We describe the preparation of unsubstituted 1 a, of 4-methoxy- (1b), and of 5-methoxynaphtho[1,2-d]-1,3-dioxole (1 c). Treatment of 1 a with bromine leads to 5-bromo-naphtho- [1,2-d]-1,3-dioxole (1d). The carboxylic acid 1f and 5-methyl-thio-naphtho[1,2-d]-1,3- dioxole (lg) are prepared by bromine-lithium-exchange from ld. Formylation yielding 1i and bromination yielding 1h show that 4-methoxy-naphtho[1,2-d]-1,3-dioxole can easily undergo electrophilic substitution. Because of less Ss-reactivity of 1c the carboxylic acid 1l and methyl-thio-naphtho[l,2-d]- 1,3-dioxole (In) can only be prepared from the lithium-compound as intermediate. Naphtho[2,3-d]-1,3-dioxole (2a) can easily undergo electrophilic substitution, showed by nitration yielding 2b, acetylation yielding 2c, bromination yielding 2d and 2e. The carboxylic acid 2j, the methyl-derivative 2k, the thionaphthole 2l, and the aldehyde 2m are prepared from the lithium-compound of 2d. Treating 2e with n-butyl-lithium leads to the dilithium-naphthyl derivative, a suitable starting material to obtain the dimethyl-compound 2n, the dicarboxylic acid 2o, and the dialdehyde 2p. Monomethyl-thio- 2q) and dimethyl-thio-naphtho[2,3-d]-1,3-dioxole (2r) are prepared in the same manner.