The invention relates to a gold electroplating solution comprising gold in the form of a complex with a compound of formula (I) or a salt thereof:

R.sup.1SArCO.sub.2H(I) Wherein: R.sup.1 is H, a C.sub.1-C.sub.6 alkyl group or SArCO.sub.2H, Ar is, at each occurrence, independently, selected from a C.sub.6-C.sub.10 arylene or a 5 to 10 membered heteroarylene group, notably a phenylene, a pyridinylene, a furanylene, a pyrrolylene, or a thienylene group.

The invention relates to a gold electroplating solution comprising gold in the form of a complex with a compound of formula (I) or a salt thereof:

R.sup.1SArCO.sub.2H(I) Wherein: R.sup.1 is H, a C.sub.1-C.sub.6 alkyl group or SArCO.sub.2H, Ar is, at each occurrence, independently, selected from a C.sub.6-C.sub.10 arylene or a 5 to 10 membered heteroarylene group, notably a phenylene, a pyridinylene, a furanylene, a pyrrolylene, or a thienylene group.