Here we present detailed evidence of highly efficient iodine capture and sensing in 1,6-disubstituted pyrene-based fluorescent conjugated microporous polymers, which were synthesized by a Sonogashira–Hagihara polycondensation reaction (TDP), trimerization reaction of a bicycano compound (CPP) catalyzed using trifluoromethanesulfonic acid (PCPP), and Friedel–Crafts reaction catalyzed with CH₃SO₃H (TTPDP and TDTPAP), respectively. TDP, PCPP, TTPDP, and TDTPAP have specific surface areas of 261.9, 43.0, 187.5, and 695.2 m² g⁻¹, and display reversible guest uptake values of 0.61, 3.07, 3.49, and 4.19 g g⁻¹ in iodine vapor, respectively. The four CMPs exhibit high sensitivity and selectivity to iodine via fluorescence quenching. Furthermore, PCPP exhibited extremely high detection sensitivity to I₂ with a K_SV of 1.40 × 10⁵ L mol⁻¹ and a detection limit of 3.14 × 10⁻¹³ mol L⁻¹. To the best of our knowledge, it displays the highest reported K_SV value and the lowest detection limit value to iodine to date.