Novel 1,4-diazine-based dyes of the D–π–A type, possessing triphenylamine as an electron-donating group, have been developed. Fluorescence studies have demonstrated that emission of these fluorophores is sensitive towards different nitroaromatic compounds and aliphatic amines, both in solutions and in a vapor phase. Moreover, these compounds can be considered as “naked-eye” fluorescent probes for solution polarity because they possess pronounced solvatochromic properties. Therefore, these compounds have to be regarded as potential multifunctional chemosensors for monitoring hazardous organic substances