The development of red solid-state fluorochromes is important for different applications. The influence of the electronic effects of substituents on the chemical shifts in the 1 H NMR spectra and solid-state fluorescent properties of aryl hydrazones of 4-hydrazino-N-hexyl-1,8-naphthalimide is evaluated. The main fragmentation pathway of hydrazones is determined using electrospray ionization mass spectrometry and high resolution MS/MS. A possible application of these fluorochromes for the in situ imaging of enzyme activities is presented.