Аннотация:Abstract A new dual responsive “turn‐on” and “ratiometric” aggregation‐induced emission luminogen (AIEgen) 3‐formyl‐5‐(piperidin‐1‐yl)biphenyl‐4‐carbonitrile 6 a (FPBC 6 a ) for selective detection of hydrazine in solution as well as in vapour phase is described. At a low concentration of 2.5 μ m , the probe FPBC 6 a is non‐fluorescent (turn‐off) but remarkably lights up (turn‐on with blue emission) in the presence of hydrazine solution (0.25–25 μ m ). Interestingly, at higher concentrations, the nanoaggregates of FPBC 6 a (>25 μ m , 99 % HEPES in DMSO) displayed ratiometric response in the presence of hydrazine with a remarkable hypsochromic shift from the green (500–550 nm) to blue regions (440–480 nm). Furthermore, a real application of FPBC 6 a was successfully demonstrated through the detection and visualization of hydrazine in live cervical cancer cells as well as using portable test strips.