An electrically-conductive pattern is prepared using a reactive composition having: (1) a reactive polymer; (2) a compound that provides a cleaving acid upon exposure to radiation; and (3) a crosslinking agent that reacts in the presence of the cleaving acid, to provide crosslinking in the reactive polymer. A polymeric layer of the reactive composition is patternwise exposed to provide a polymeric layer comprising non-exposed regions and exposed regions comprising a polymer comprising sulfonic acid or sulfonate groups. The exposed regions are contacted with electroless seed metal ions to form a pattern of electroless seed metal ions, which pattern is reduced to provide a pattern of corresponding electroless seed metal particles. Electrolessly plating is then carried out in the exposed regions. The unique reactive comprises (a) recurring units represented Structure (A) as described in the disclosure, and can also include other recurring units that are crosslinkable or provide other properties.