I recently learned that my Ohio city taxes "[a]ny amount not included in wages because the amount arises from the sale, exchange, or other disposition of a stock option, the exercise of a stock option, or the sale, exchange, or other disposition of stock purchased under a stock option."
I never considered participation in an Employee Stock Purchase Plan (ESPP) a stock option in the same sense as an Incentive Stock Option (ISO) grant. But reading this IRS Topic, it looks like they both would get hit by the city income tax.
I guess I answered my own question, but looking for your confirmation.