In the title compound, C14H10ClNOS, the dihedral angle between the benzothia­zole ring system and the meth­oxy-substituted benzene ring is 8.76 (16)°. In the crystal, mol­ecules are stacked in columns along the c axis and no significant inter­molecular inter­actions are observed.

In the title compound, C16H14ClNO3S, the dihedral angle between the almost-planar benzothia­zole ring system [maximum deviation = 0.012 (3) Å] and the aromatic ring of the trimeth­oxy­phenyl group is 15.56 (6)°. In the crystal, the mol­ecules are arranged into layers parallel to the bc plane, held together only by weak van der Waals forces.

In the title compound, C15H14O4, the chromone ring system is close to being planar [maximum deviation = 0.015 (2) Å]. The double bond of the ethyl prop-2-enoate chain adopts an E conformation and an intra­molecular C—H⋯O hydrogen bond generates an S6 ring. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds generate R 2 2(14) loops. Weak π–π inter­actions [centroid–centroid distance = 3.8493 (12) Å] also occur.

In the title compound, C11H8O3, the benzopyran-4-one or chromone ring system is almost planar, with a maximum deviation of 0.045 (2) Å. The crystal structure is stablized by π–π inter­actions between the benzene and pyran rings of inversion-related mol­ecules stacked along the b axis, with a centroid–centroid distance of 3.5463 (12) Å

In the mol­ecule of the title compound, C14H10ClNO2S, the dihedral angle between the almost planar benzothia­zole ring system [maximum deviation = 0.005 (2) Å] and the benzene ring is 1.23 (9)°. The conformation of the mol­ecule is stabilized by an intra­molecular O—H⋯N hydrogen bond, forming an S(6) ring motif. In the crystal, mol­ecules are linked into layers parallel to the ac plane by C—H⋯O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distance = 3.7365 (12) Å].

In the structure of the title compound, C13H8ClNS, the dihedral angle between the benzothia­zole ring system and the phenyl ring is 7.11 (8)°. In the crystal, mol­ecules are arranged parallel to the c axis.

In the title compound, C15H14O4S, the dihedral angle between the benzene and phenyl rings is 88.74 (10)°. In the crystal, mol­ecules are linked into a three-dimensional network by C—H⋯O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distances = 3.6092 (13)–3.8651 (13) Å].

The title compound, C21H23NO3, is a phenyl­imine derivative of the well known anthelmintic agent α-santonin. The trans-fused cyclo­hexane and γ-lactone rings of the α-santonin ring system adopt chair and envelope conformations, respectively, whereas the hexa­diene ring is approximately planar [maximum deviation = 0.029 (4) Å] and forms a dihedral angle of 62.30 (11)° with the benzene ring. An intra­molecular O—H⋯N hydrogen bond is observed.

The title compound, C21H24N2O2, is a phenyl hydrazine derivative of the well known anthelminthic agent α-santonin, which is composed of three fused rings (benzodieneone, cyclo­hexane and γ-lactone). The cyclo­hexa­dienone ring adopts a boat conformation, the cyclo­hexane ring is in a chair conformation and the trans-fused γ-lactone ring adopts a C-envelope conformation. In the crystal, mol­ecules are linked by N—H⋯O and C—H⋯O hydrogen bonds, forming chains along the a axis.

Cellulose fiber is a tremendous natural resource that has broad application in various productions including the textile industry. The dyes, which are commonly used for cellulose printing, are “reactive dyes” because of their high wet fastness and brilliant colors. The interaction of various dyes with the cellulose fiber depends upon the physiochemical properties that are governed by specific features of the dye molecule. The binding pattern of the reactive dye with cellulose fiber is called the ligand-receptor concept. In the current study, the three dimensional quantitative structure property relationship (3D-QSPR) technique was applied to understand the red reactive dyes interactions with the cellulose by the Comparative Molecular Field Analysis (CoMFA) method. This method was successfully utilized to predict a reliable model. The predicted model gives satisfactory statistical results and in the light of these, it was further analyzed. Additionally, the graphical outcomes (contour maps) help us to understand the modification pattern and to correlate the structural changes with respect to the absorptivity. Furthermore, the final selected model has potential to assist in understanding the charachteristics of the external test set. The study could be helpful to design new reactive dyes with better affinity and selectivity for the cellulose fiber.