I think you are asking if a company is eligible to use the dividends it paid as an expense to reduce the corporation tax it will be pay, right? If yes, then no it can not use the dividends as an expense so dividends are not tax deductible.
The dividends are distributed after all expenses are paid and after the tax is calculated and it’s a way to distribute the profits that are attributable to the shareholders so they are not an expense but just a way to withdraw the profits from the company.