Ohio Rev. Code § 5747.77
The credit shall be claimed in the order required under section 5747.98 of the Revised Code. If a credit exceeds the aggregate amount of tax otherwise due for a taxable year, the excess may be carried forward and applied against the tax due for not more than seven succeeding taxable years, provided that the amount applied to the tax due for any taxable year shall be subtracted from the amount available to carry forward to succeeding years.
The credit shall be claimed in the order required under section 5747.98 of the Revised Code. If a credit exceeds the aggregate amount of tax otherwise due for the taxable year, the excess may be carried forward and applied against the tax due for not more than three succeeding taxable years, provided that the amount applied to the tax due for any taxable year shall be subtracted from the amount available to carry forward to succeeding years.
R.C. § 5747.77