N.Y. Comp. Codes R. & Regs. tit. 20, § 152.2
The due date for the filing of a New York State income tax return is the last day upon which such return is required to be filed in accordance with this Subchapter, or the last day of the period covered by any extension of time allowed under Part 157 of this Article. As to the due date for payment of the income tax, see sections 152.14-152.18 of this Part.