Electrophilic aromatic nitration under mild conditions of 4-hydroxyphthalonitrile gave 4- hydroxy-3-nitrophthalonitrile and 4-hydroxy-5-nitrophthalonitrile, while bromination yielded 3- bromo-4-hydroxyphthalonitrile, 4-bromo-5-hydroxyphthalonitrile, and 3, 5-dibromo-4- hydroxyphthalonitrile. Iodination gave 4-hydroxy-5-iodophthalonitrile and 4-hydroxy-3, 5- diidophthalonitrile. Coupling of 4-iodophthalonitrile, 3-iodophthalonitrile, and 5-iodo-2, 3- ...