A sustainable biomass economy requires the development of different integrated steps for the conversion of biomass-derived feedstocks into a range of fuels and chemicals. Many of these steps involve basic catalysts. One key step in biorefinery concept to produce diesel and jet fuel range alkanes involves C-C bond forming reactions by aldol condensation. In this research, we present two types of novel solid base catalysts for both the liquid and gas phase aldol condensation reactions: the nitrogen-substituted zeolites and silica supported CeZrOx. Furaldehydes condensation with acetone or propanal was studied in liquid phase over the nitrogen-substituted NaY (Nit-NaY) and MgO-ZrO2, a mixed metal oxide. Nit-NaY showed comparable catalytic activity to MgO-ZrO2, but higher selectivity to furadehyde acetone monomer product, indicating the shape selective significance of Nit-NaY. In the gas phase aldol condensation reaction, butanal was selected as model compound to generate C8 to C12 hydrocarbon compounds. CeZrOx/SiO2 lowers the reaction temperature about 100°C and is very stable towards acid poisoning compared to MgO/SiO2. The nature of the basic sites, the reaction chemistries and reaction mechanisms were also investigated.