This dissertation describes a compositional model rooted in cross-influential methodology between complementary musical compositions that share generative source material. In their simultaneous construction, two composition pairs presented challenges that influenced and mediated the other's development with respect to timbre, transposition, pitch material, effects processing, and form. A working prototype first provides a model that is later developed. The first work Thema is for piano alone, and the companion piece Am3ht is for piano and live computer processing via the graphical programming environment Max/MSP. Compositional processes used in the prototype solidify the cross-influential model, demanding flexibility and a dialectic approach. Ideas set forth in the prototype are then explored through a second pair of compositions rooted in cross-influential methodology. The first work Lusmore is scored for solo contrabass and Max/MSP. The second composition Knockgrafton is scored for string orchestra. The flexibility of the cross-influential model is revealed more fully through a discussion of each work's musical development. The utility of the cross-influential compositional model is discussed, particularly within higher academia.