Intrinsic emission from nonconventional luminophores without classic remarkable conjugation has aroused increasing attention due to its significant fundamental importance and promising applications. These nonconventional luminophores generally contain the heteroatoms(i.e. N, O, S, P), unsaturated units of C≡N, C=O, C=C, etc., and their grouped moieties(i.e. hydroxyl, amino, ester, anhydride, amide, uramido, oxime, sulfone). In recent years, despite great progress has been achieved, the emission mechanism still remains under debate. Previously, we proposed the clustering-triggered emission(CTE) mechanism, namely the clustering of nonconventional chromophores with π and n electrons and subsequent through space conjugation result in extended electron delocalization and conformation rigidification, to rationalize the emission. Herein, based on the CTE mechanism, we review such typical emission characteristics of nonconventional luminophores as concentration enhanced emission, aggregation-induced emission(AIE), excitation-dependent emission, and phosphorescence. It is also noted that CTE mechanism can be used to rationalize the photophysical behaviors of different types of nonconventional luminophores of natural products, synthetic compounds, and biomolecules. Furthermore, it is also helpful to guide the rational discovery or design of new nonconventional luminogens. In addition, we briefly summarize the progress of different kinds of nonconventional luminophores. Finally, the perspectives of this emerging area are also discussed.