Why is the melting point of TiCl4 lower than TiCl3
-The high melting point of  $\ce{TiCl3}$
is mainly due to the short bond length $\ce{Ti-Ti}$ , which infer
 a strong metallic character to these bonds between titanium ions in  $\ce{TiCl3}$.

-While in $\ce{TiCl4}$, the main intermolecular forces are of van der Waals type.