Abstract: The present study highlights the synthesis, single crystal structure and complete spectral characterization of two heteroaryl chalcones, namely (i) (E)-3-(benzo[b]thiophen-3-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one (C17H12O2S) and (ii) (E)-1-(2-aminophenyl)-3-(benzo[b]thio phen-3-yl)prop-2-en-1-one (C17H13NOS). In both of these compounds, the molecules show weak intermolecular C–H···O interactions utilizing the keto group in addition to hydrogen bonding including hydroxyl and amino groups. In the case of compound (ii) water molecules are trapped in voids of the crystal lattice. π–π stacking interactions between phenyl and benzothiazole rings are observed in the crystal packing. In addition to crystallographic data, both the structures are also described for the first time with 1H NMR, H–H Cosy, 13C NMR, DEPT-135, HR-MS, TGA-DTG, DSC, IR and UV spectral data. Graphical Abstract: The synthesis, single crystal structure and complete spectral characterization of benzo[b]thiophene-3-carbaldehyde based novel heteroaryl chalcones.[Figure not available: see fulltext.] © 2016, Springer Science+Business Media New York.