Employing in situ N‐alkylation of the conjugated compound 9,10‐bis(4‐pyridyl)anthracene (bpanth) as structure‐directing agent, a 3D inorganic‐organic hybrid iodoplumbate, [Me2(bpanth)][Pb4I10] (1), was solvothermally prepared. The in situ N‐alkylation of bpanth with alcohols was investigated. 1 features a novel 3D open framework based on an interesting Pb6I24 cluster. UV/Vis spectroscopy analyses indicate that 1 is a potential semiconductor material with a narrow energy gap of 2.06 eV. It exhibits good catalytic activity in the visible‐light‐drived degradation of an organic dye. This work further illustrates that introducing conjugated organic molecules as templates is conducive to achieving semiconducting hybrid halometallates with narrow band gaps.