As a fluorescent inorganic–organic hybrid polymer, cross-linked poly(tetraphenylethylene-co-cyclotriphosphazene) (TPE-CP) is prepared through one-step polycondensation and well characterized. Owing to the aggregation-induced emission feature of the tetraphenylethylene residue, TPE-CP exhibits a remarkable fluorescent emission property in the suspension and solid-state. Both 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (picric acid, PA) can cause a significant fluorescence quenching of TPE-CP due to the electron transfer from TPE-CP to TNT or PA. Additional energy transfer makes PA more sensitive to TPE-CP than TNT in the fluorescence quenching detection.