They don't have to match, but it would be an unorthodox approach. The great thing about paint, however, is that it's relatively easy to change back. You'd probably know whether or not you like the look after painting just the street side of one column.
Some hanging flower baskets around the perimeter of the porch could be a nice way to energize the area if you're considering options other than paint.
Some hanging flower baskets around the perimeter of the porch could be a nice way to energize the area if you're considering options other than paint.