Abstract Modular synthesis can combine different functional modules to flexibly regulate comprehensive properties and study the diversity of compounds. This study established a modular bicyclic synthesis strategy of combining polynitro energetic module with iodine‐containing biocidal module. Compounds 1 – 6 with high iodine content (48.72–69.56 %) and high thermal stability (T d : 172–304 °C) were synthesized and exhaustively identified. By modular synthesis, the detonation properties and gas‐production of 3 – 6 improved greatly expanding their biocidal efficacy and maintained the iodine atomic utilization of iodine‐containing module. Notably, 4,5‐diiodo‐3,4’,5’‐trinitro‐1,3’‐bipyrazole ( 5 ) and 3,5‐diiodo‐4,4’,5’‐trinitro‐1,3’‐bipyrazole ( 6 ) exhibit high detonation velocities ( D : 5903 m s −1 , 5769 m s −1 , respectively) and highest gas production of 212.85 L mol −1 and 217.66 L mol −1 after decomposition. This study diversifies polyiodio‐nitro compounds, and also inspire the implementation of similar synthesis strategies to provide family‐level synthetic solutions to energetic biocidal materials.