Molecular templating offers a means of tailoring the pore space geometry of disordered materials. We present here a theoretical description of the available volume (porosity) for adsorption created by chain molecule templates. Our model material is a quenched, equilibrated hard-sphere/tangent hard-sphere chain mixture configuration with the chain molecules removed. We extend a diagrammatic theory [P. R. Van Tassel, Phys. Rev. E. 60, R25 (1999)], previously used for a hard-sphere template, to this system and obtain the required correlation functions from the polymer Percus-Yevick theory of a sticky two-point associating fluid mixture within an ideal chain approximation. We also apply Monte Carlo simulation. We find that the available volume increases with template length and that this is most pronounced for a small chain length (n less than or equal to4), a large template:matrix ratio, and a large adsorbate size. (C) 2001 American Institute of Physics.