When it comes to thinking sentimentally, there are a variety of synonyms that can be used to convey the same sentiment. Some potential synonyms might include thinking nostalgically, thinking wistfully, or thinking romantically. Other potential options might include thinking emotionally, thinking affectionately, or thinking sentimentally. Alternatively, one might use the term reminiscing or reflecting to capture the same essence of sentimentality. Ultimately, no matter which synonym one chooses to use, the goal is to convey a sense of affectionate or emotional contemplation that reflects on the past or present with a sense of fondness or sentimentality.