A method of characterizing candidate agents including steps of (a) providing a library of candidate agents attached to nucleic acid tags; (b) contacting the library with a solid support to attach the candidate agents to the solid support, whereby an array of candidate agents is formed; (c) contacting the array with a screening agent, wherein one or more candidate agents in the array react with the screening agent; (d) detecting the array to determine that at least one candidate agent in the array reacts with the screening agent; (e) sequencing the nucleic acid tag to determine the tag sequences attached to candidate agents in the array; and (f) identifying the at least one candidate agent in the array that reacts with the screening agent based on the tag sequence that is attached to the at least one candidate agent.