Through manipulating crystal growth directions, we devised a versatile synthetic method to fabricate complex alpha-MoO3 nanostructures with external bonding capacity for self-organization. Using four-armed forklike alpha-MoO3 as nanobuilding blocks, we assembled more complex crystal morphologies, such as centrally holed nanorods, tridents, and paintbrushes. With prolonged ultrasonic treatments, pristine forklike alpha-MoO3 crystals can be turned into less armed nanostructures, giving away the secondary arms (width < 100 nm) at the same time. On the other hand, the resultant alpha-MoO3 itself can act as a template to produce shaped TiO2 and other nanocrystals. Square- and horseshoe-shaped nanocrystals of anatase TiO2 are left undissolved after removing alpha-MoO3 templates in basic medium.