Chlorinated polyolefins are commonly used to promote adhesion of subsequent paint layers to thermoplastic polyolefins (TPO). In certain instances, flame, plasma, or chemical treatments are also used to increase the surface free energy of the TPO so that the subsequent coating adhesion performance is enhanced. Elimination of the intervening steps required for adhesion promotion would result in cost savings and VOC reduction for the production facilities involved in painting substrates. Basecoat formulations have been developed which have passed the initial requirements for a commercial TPO / paint system without adhesion promoter. This is accomplished by modifying the basecoat formulations with olefinic diol. Initial performance results for these new olefinic basecoats over TPO will be presented.