Topochemical reactions can be effectively conducted without additional reagents and solvation requirements. Hence, they are attractive in various fields of modern chemistry. However, there remains a lack of ways to precisely control the degree upon topochemical polymerization or oligomerization. As compared with yielded z-structured polymers, a slight difference in repeating unit of their oligomeric counterparts can normally connect to distinct visualized optoelectronic properties in the UV-vis region. Therefore, we herein report that the well-selected biomacro-molecular templates were straightforwardly employed to attain a precise control of topochemical photooligomerization degree for a series of uniform oligomeric pi-functional materials. A diphenyldiacetylene prototype was designed and electrostatically interacted with BSA (albumin from bovine serum), DNA (calf thymus), and HS (heparin sodium), and their binding constant exhibited a progressive order of magnitude. In this way, photooligomerization control for uniquely forming corresponding dimeric and trimeric oligodiacetylenes can be successfully achieved upon photoirradiation with the template optimized from the perspective of adjustable dynamic equilibrium. Furthermore, two of the oligodiacetylene species reveal blue and yellow fluorescence and therefore can be applied into selective and multichannel bioimaging with good biocompatibility on account of their biomacromolecular templates, featuring the advantage of obtaining species with repeating-unit difference for material applications.