In 3,6-di(p-chlorophenyl)-2,7-dihydro-1,4,5-thiadiazepine, C₁₆H₁₂Cl₂N₂S, which crystallizes in the triclinic space group, P-1, with a = 8.4012(13) Å, b = 9.2087(15) Å, c = 10.4974(17) Å, α = 69.835(3)°, β = 77.091(4)°, γ = 81.820(4)°, V = 741.2(2) ų and Z = 2, the seven-membered ring adopts a distorted boat conformation. The structure was solved by direct methods and refined by full-matrix least squares based on F² with weight w = 1/[σ²( \textF_\texto² {\text{F}}_{\text{o}}^{2} ) + (0.0018P)² + 1.5600P] where P = ( \textF_\texto² {\text{F}}_{\text{o}}^{2}  +  2 \textF_\textc² 2 {\text{F}}_{\text{c}}^{2} )/3. The new d_norm Hirshfeld surface and the breakdown of fingerprint plots were used for visualizing and exploring of title compound for quantifying intermolecular interactions in crystal lattice.

Crystal structure and Hirshfeld surface analysis of 3,6-di(p-chlorophenyl)-2,7-dihydro-1,4,5-thiadiazepine have been reported.