We show how objects typically used to study surfaces can be used to give insights into the structure of smooth 4–manifolds. In particular, we construct a correspondence between loops in the pants complex and smooth, closed, oriented 4–manifolds. We use this correspondence, together with the fact that the pants complex is simply connected, to show that the cobordism group of such 4–manifolds is isomorphic to the integers. We also discuss how this correspondence can be used to give insights into the structure of the pants complex.