The term complex polygon can mean two different things:

In geometry, a complex polygon is a polygon in the complex Hilbert plane, which has two complex dimensions.

A complex number may be represented in the form ${\displaystyle (a+ib)}$, where ${\displaystyle a}$ and ${\displaystyle b}$ are real numbers, and ${\displaystyle i}$ is the square root of ${\displaystyle -1}$. Multiples of ${\displaystyle i}$ such as ${\displaystyle ib}$ are called imaginary numbers. A complex number lies in a complex plane having one real and one imaginary dimension, which may be represented as an Argand diagram. So a single complex dimension comprises two spatial dimensions, but of different kinds - one real and the other imaginary.

The unitary plane comprises two such complex planes, which are orthogonal to each other. Thus it has two real dimensions and two imaginary dimensions.

A complex polygon is a (complex) two-dimensional (i.e. four spatial dimensions) analogue of a real polygon. As such it is an example of the more general complex polytope in any number of complex dimensions.

In a real plane, a visible figure can be constructed as the real conjugate of some complex polygon.

In computer graphics, a complex polygon is a polygon which has a boundary comprising discrete circuits, such as a polygon with a hole in it.

Self-intersecting polygons are also sometimes included among the complex polygons. Vertices are only counted at the ends of edges, not where edges intersect in space.