In JLAtg for biblical זֶה when it means "now".
The Geonic/LJLA usage surely is a hypercorrection by misunderstanding of the literary form as being equivalent to דנא. Only in the expression יומא דנן, i.e. as an expression of time, might the form be correct in the Babylonian literary dialect, otherwise it should be viewed as archaic and highly formulaic, possibly reflecting the relatively common usage with personal names in the magic bowl tradition.