Effects of nine incorporated n-alkane derivatives on molecular packing and phase behavior of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers were investigated using wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The incorporation commonly resulted in closer packing of the lipid alkyl chains in the ordered phase and shift of the thermal anomaly due to the main transition to a higher temperature. These common features suggest that effects of incorporated molecules on structure and phase behavior of DPPC bilayers can be classified by their shape.