The results of a comparative study of nanowires grown on single crystalline substrates from para-hexaphenylene, alpha-sexithiophene, and 5,5(')-Di-4-biphenyl-2,2(')-bithiophene are presented. Due to their interesting optical properties such nanowires are of importance for future integrated optoelectronic devices. From atomic force microscopy and polarized far-field optical microscopy data, it is deduced that epitaxy and electrostatic interactions determine the microscopic growth mechanism, whereas kinetics ascertains the macroscopic habit. Understanding such basic growth principles for these systems allows one to predict qualitatively nanowire surface growth from other conjugated molecules and thus allows for a sophisticated design of new devices. (C) 2008 American Vacuum Society.