We consider N = 1 SU (N c ) gauge theory with an adjoint matter field Φ, N f flavors of fundamentals Q and antifundamentalsQ, and tree-level superpotential of the formQΦ l Q. This superpotential is relevant or marginal for lN f ≤ 2N c . The theory has a Coulomb branch which is not lifted by quantum corrections. We find the exact effective gauge coupling on the Coulomb branch in terms of a family of hyperelliptic curves, thus providing a generalization of known results about N = 2 SUSY QCD to N = 1 context. The Coulomb branch has singular points at which mutually nonlocal dyons become massless. These singularities presumably correspond to new N = 1 superconformal fixed points. We discuss them in some detail for N c = 2, N f = 1.