Efficient synthetic route to 1,3-dialkynyl- and 1,3-dialkenyl-isobenzofurans, new pi-extended congeners of isobenzofurans, was reported. A three-step protocol including double nucleophilic additions of alkynyllithiums to o-phthalaldehyde and selective oxidation enables us to prepare various functionalized p-extended isobenzofurans. The photophysical properties of these p-extended isobenzofurans are also evaluated.