Alkylquinolines are ubiquitous in functional products. However, the direct and selective alkylation of quinolines has to date remained a challenge. Herein, by developing a new catalyst composing of cobalt oxides supported on N-Si-doped titanium dioxide (CoOx/N-Si-TiO2), we present, for the first time, its application toward hydrogen transfer-mediated dual beta-alkylations of 2-alkylquinolines with various aldehydes. The developed chemistry allows a direct access to a wide array of 2,3-dialkylquinolines in conjunction with the features of good substrate and functional group compatibility, high regio and chemo-selectivity, the use of naturally abundant and reusable heterogeneous cobalt catalyst, and the generation of H2O as the by-product, which has demonstrated the potential in direct functionalization of multiple heteroaryl C-H bonds by the combination of heterogeneous catalyst design with reductive dearomatization as an activating mode of N-heteroarenes. (C) 2019 Elsevier Inc. All rights reserved.