Benzoxepin compounds of Formula I, and including stereoisomers, geometric isomers, tautomers, solvates, metabolites and pharmaceutically acceptable salts thereof, wherein: Z1 is CR1 or N; Z2 is CR2 or N; Z3 is CR3 or N; Z4 is CR4 or N; and where (i) X1 is N and X2 is S, (ii) X1 is S and X2 is N, (iii) X1 is CR7 and X2 is S, (iv) X1 is S and X2 is CR7; (v) X1 is NR8 and X2 is N, (vi) X1 is N and X2 is NR8, (vii) X1 is CR7 and X2 is O, (viii) X1 is O and X2 is CR7, (ix) X1 is CR7 and X2 is C(R7)2, (x) X1 is C(R7)2 and X2 is CR7; (xi) X1 is N and X2 is O, or (xii) X1 is O and X2 is N, are useful for inhibiting lipid kinases including p110 alpha and other isoforms of PI3K, and for treating disorders such as cancer mediated by lipid kinases. Methods of using compounds of Formula I for in vitro, in situ, and in vivo diagnosis, prevention or treatment of such disorders in mammalian cells, or associated pathological conditions, are disclosed.