Per the divorce my ex and I get to each claim one of the two kids as a dependent. However I am paying for about 70% of the dependent care expenses, while she pays the rest. Am I able to claim those expenses (70% for my dependent and 70% for the other child) on my return even if one of the kids isn't my dependent for filing purposes??? Our divorce decree only speaks to claiming the exemptions and filing status, not any credits or deductions.
The IRS is the ultimate authority as far as tax credits and deductions are concerned. Credits associated with children are handled in a special way when the parents are divorced, separated, or living apart. For the Child and Dependent Care Credit (CDCC), it doesn't matter which parent claims the child as a dependent. The CDCC always goes to the custodial parent. The IRS definition of custodial parent is the parent with whom the child spent more nights during the tax year. If your child spent more than half of the nights with you (specifically, 183 or more nights in 2017), you may claim the child care expenses whether you claimed the child as a dependent on your tax return or not. For more information, please see Who is a Qualifying Person for the Child and Dependent Care Credit?