Tax Law, § 651(c)

The due date for filing a New York State income tax return for a decedent, covering the period which ended with his death, is the same as if he had lived until the end of his normal taxable year. If he reported on a calendar-year basis and died during the taxable year, the New York State income tax return, covering the period from January first until his death, is due on April 15th of the succeeding year, regardless of whether his death occurred early in the taxable year or on the last day of that year. Such return may be filed at any time after the appointment and qualification of the executor or administrator and without waiting for the close of the decedent's normal taxable year. If a surviving husband or wife meets the provisions of section 151.11(b) of this Article and properly files a joint New York State personal income tax return with the deceased spouse, the due date for such joint return is the 15th day of the fourth month following the close of the taxable year of the surviving spouse.