The Collaborative International Dictionary of English v.0.48:

Schismatize \Schis"ma*tize\, v. i. [imp. & p. p. Schismatized;
   p. pr. & vb. n. Schismatizing.] [Cf. F. schismatiser.]
   To take part in schism; to make a breach of communion in the
   church.
   [1913 Webster]