California Code, Revenue and Taxation Code - RTC § 23503

There shall be offset against the tax hereby imposed for any period the amount of any tax imposed on the taxpayer under Chapter 2  1 for the same period. In the event that taxes, interest and penalties have been or shall be assessed against, paid by or collected from a taxpayer under this chapter, which assessment, payment or collection should have been made under Chapter 2, such taxes, interest and penalties shall be considered as having been assessed, paid or collected under Chapter 2 as of the date or dates they were made.