Can i deduct contributions to a 529 plan in ny state even if the 529 plan is from Illinois?

[KrisD]

Yes.

"Remember, you don’t have to use your home state’s plan and you can use a 529 college savings plan to pay for an eligible institution in any state."

https://www.savingforcollege.com/article/529-plan-contribution-deadlines-for-state-tax-benefits