yes it will offset some of the gain from selling property. assuming what you donated was capital gain property, you can only use an amount = 30% of adjusted gross income. or the limit could be 20% or something else.
not knowing any details about the contribution makes it impossible to give you an exact answer.
i have provided a link to IRS PUB 526 which discusses charitable contributions in more detail. This also assumes that your itemized deductions will exceed your standard deduction.
https://www.irs.gov/pub/irs-pdf/p526.pdf
