This に is a conjunctive particle that lists two predicates, indicating that the second item is added to the first. It is similar to 'and' or 'moreover', and it often implies that both actions or states are performed or true, sometimes with a sense of 'doing both' or 'being both'. It is a formal, written-style pattern, rarely used in casual conversation. The second clause often ends with an evaluative or conclusive expression, like 悪い, 疲れる, or a negative judgment. For example, it can express that something is 'both A and B', or that one does 'A and B' in addition. Note that this に is different from the particle に that marks destination or location (e.g., 学校に行く). That に is unrelated and much more common. This conjunctive に is a separate grammar point, typically found in formal writing or speeches.