If you cut back and omit the 2nd 1/2 cup, you will have to replace the liquid equivalent. Depending on what you are making, golden syrup or honey would probably have the right chemistry but would likely come out sweeter. Taste, add in the sweetener substitute gradually, so you can get the balance where you want it. Also, judge by the consistency of the batter (if that's what you're making).

and by "altogether" i meant that last half cup of molasses, not all of the molasses : )

it depends on what you're making. you might be able to substitute in honey or actually leave it out altogether.

Maybe add brown sugar to the syrup.