The structures of seven gold(III) halide derivatives of general formula L Au X 3 ( L = methyl-pyridines or di-methyl-pyridines, X = Cl or Br) are presented: tri-chlorido-(2-methyl-pyridine)-gold(III), [AuCl 3 (C 6 H 7 N)], 1 (as two polymorphs 1a and 1b ); tri-bromido-(2-methyl-pyridine)-gold(III), [AuBr 3 (C 6 H 7 N)], 2 ; tri-bromido-(3-methyl-pyridine)-gold(III), [AuBr 3 (C 6 H 7 N)], 3 ; tri-bromido-(2,4-di-meth-yl-pyridine)-gold(III), [AuBr 3 (C 7 H 9 N)], 4 ; tri-chlorido-(3,5-di-methylpyridine)-gold(III), [AuCl 3 (C 7 H 9 N)], 5 ; tri-bromido-(3,5-di-methyl-pyridine)-gold(III), [AuBr 3 (C 7 H 9 N)], 6 , and tri-chlorido-(2,6-di-methyl-pyridine)-gold(III), [AuCl 3 (C 7 H 9 N)], 7 . Additionally, the structure of 8 , the 1:1 adduct of 2 and 6 , [AuBr 3 (C 6 H 7 N)]·[AuBr 3 (C 7 H 9 N)], is included. All the structures crystallize solvent-free, and all have Z ' = 1 except for 5 and 7 , which display crystallographic twofold rotation symmetry, and 4 , which has Z ' = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals ( 1a , 1b , 2 and 8 ) were non-merohedral twins, and these structures were refined using the 'HKLF 5' method. The largest inter-planar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the pyridine ring. The Au-N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au- X ) 2 , with anti-parallel Au- X bonds linked by Au⋯ X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary inter-actions (Au⋯ X or X ⋯ X contacts, 'weak' C-H⋯ X hydrogen bonds) to form chain, double chain ('ladder') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C-H⋯Cl hydrogen bonds combined with Cl⋯Cl contacts ( 1b ) or Cl⋯π contacts ( 7 ). The packing patterns of seven further complexes L Au X 3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1 - 8 .