The effect of substitution in the phenyl ring on the crystal systems of amides of the type, 2/4-XC 6 H 4 -NHCO-CHCl 2 (X = H, Cl or CH 3 ), has been studied by determining the crystal structures of the compounds, iV-(phenyl)-2,2-dichloroacetamide, C 6 H 5 -NHCO-CHCl 2 (PhDCA); N-(2-chlorophenyl)-2,2-dichloroacetamide, 2-ClC 6 H 4 -NHCO-CHCl 2 (o-ClPhDCA), jY-(4-chlorophenyl)-2,2-dichloroacetamide, 4-ClC 6 H 4 -NHCO-CHCl 2 (p-ClPhDCA) and N -(4-methylphenyl)-2,2-dichloroacetamide, 4-CH 3 C 6 H 4 -NHCO-CHCl 2 (p-CH 3 PhDCA) and analysed the data along with our earlier crystal structures of the compounds, N-(phenyl)-2,2,2-trichloro-acetamide (PhTCA), N-(2-chlorophenyl)-2,2,2-trichloroacetamide (o-ClPhTCA), N -(4-chloro-phenyl)-2,2,2-trichloroacetamide (p-ClPhTCA), N-(4-methylphenyl)-2,2,2-trichloroacetamide (p-CH 3 PhTCA); N-chloro-N-(phenyl)-2,2-dichloroacetamide (NClPhDCA), N-chloro-N-(phenyl)-2,2,2-trichloroacetamide (NClPhTCA) and N-(phenyl) acetamide (PhA). The crystal type, space group, formula units and lattice constants in A of the new structures are; PhDCA: monoclinic, P 2 1 /c, Z = 4, a = 8.785(3), b = 11.139(4), c = 9.521(3), ß = 97.47(2)°; o-CIPhDCA: monoclinic, P 2 1 /c, Z = 4, a = 4.711(2), b = 11.234(6), c = 19.191(8), ß = 98.12(2)°; p-CIPhDCA: monoclinic, P 2 1 /c, Z = 8, a = 18.627(5), b = 11.533(3), c = 9.583(3), ß = 102.43(2)°, and /?-CH 3 PhDCA: orthorhombic, Pbca, Z = 8, a = 9.464(3), b = 9.894(3), c = 21.973(7). The compound p-ClPhDCA shows two molecules in its asymmetric unit. This is in agreement with the multiple lines observed in the 35 Cl NQR spectra of the compound. The crystal systems of the chlorosubstituted and methyl substituted chloroacetamides get interchanged on replacement of the side chain -CHCl 2 by -CCl 3 . C(i)-C(j) ring distances show no significant variations with the substitution either at the side chain or in the phenyl ring. C(ring)-N and C (0)-N bond distances are also not much affected by either ring or side chain substitution, but are affected by N-chlorination, while the C -0 bond length is slightly shortened by the replacement of the -CH 3 group by -CCl 3 , the introduction of electron withdrawing group into the phenyl ring or by N-chlorination. Deviations of C2(ring)-Cl(ring)-N, C6(ring)-Cl(ring)-N and C (ring)-N-C(0) bond angles from 120° narrow down on substitution either in the phenyl ring or in the side chain, but the latter increases on W-chlorination of the compounds.