Black pants match well with shirts that are brightly colored such as white, red or royal blue. Shirts with bold patterns also look good with black pants.
Black is one of the easiest colors to match. Bright jeweled tones look best. These include colors such as ruby/burgundy, sapphire blue and emerald green. If the pants are plain, with no pattern, then bold patterned shirts really pop. For pants that are striped or checked, stick with shirts with no design. This avoids any potential clashing of patterns, which causes the entire outfit to look busy and haphazard.
In addition to the color of the shirt, one should also consider its style. For example, if the black pants are a dressy wool trouser, then a short-sleeved casual shirt is not the best choice regardless of the color. On the other hand, a pair of black skinny jeans looks great paired with a tank top in a bright color.
It may be a good idea, however, to stay away from wearing a pastel shirt with a pair of black pants. Pastels are subdued and the black pants tend to wash out the color even more. Also, stay away from wearing a black-on-black outfit. Unless the hue of the black shirt matches the black pants exactly, the look ends up mismatched and sloppy.