A porous material includes a polyhexahydrotriazine material. Pores in the porous material can be of various sizes including nanoscale sizes. The porous material may be used in a variety of applications, such as those requiring materials with a high strength-to-weight ratio. The porous material can include a filler material dispersed therein. The filler material can be, for example, a particle, a fiber, a fabric, or the like. In some examples, the filler material can be a carbon fiber or a carbon nanotube. A method of making a porous material includes forming a resin including a polyhemiaminal or polyhexahydrotriazine component and a polythioaminal component. The resin can be heated to promote segregation of the components into different phases with predominately one or the other component in each phase. Processing of the resin after phase segregation to decompose the polythioaminal component can form pores in the resin.