Graphical Abstract: The research is devoted to the study of unexpected products that formed as a result of the condensation reaction between 2-acetylpyridine and 2-formylpyridine under the Claisen-Schmidt reaction conditions. As a result, a sequence of reactions leading to the following compounds has been proposed: 1,3-bis (pyridin-2-yl) prop-2-en-1-one (3); 1,3,5-tri (pyridin-2-yl) pentane-1,5-dione (4); (2,4-dihydroxy-2,4,6-tri(pyridin-2-yl)cyclohexyl)(pyridin-2-yl)methanone (5) and (4-hydroxy-2,4,6-tri(pyridin-2-yl)cyclohexane-1,3-diyl)bis(pyridin-2-ylmethanone) (6) as well as 2-formylpyridine (1) and 2-acetylpyridine (2). The plausible mechanism of these chemical transformations has been proposed. All the obtained compounds demonstrate moderate antimicrobial, antifungal and antioxidant activity.