Abstract. Asai and Friedberg studied the imaginary Doi-Naganuma lifting which sends
elliptic modular forms to automorphic forms over an imaginary quadratic eld. In this
paper we extend this lifting to weak Maass forms by using regularized integral. We
construct an automorphic object with singularities on the quadratic upper half-plane H1
by the regularized theta lifting of a weak Maass form. We also give the convergence
region and describe its singularity type. Finally we compute the Fourier coecients of
the lifted form explicitly and present the case of Poincare series as an example.