@Helium5793 Are these i) large batches of input files to generate and ii) are the instructions to deliver to MOPAC per batch the same? Do you feel comfortable with the command line?

Let’s assume you have two structure files, benzene.xyz and pyridine.xyz in one folder, and you have openbabel at hand, you can convert the two into .mop

$ obabel *.xyz -O .mop -m
2 molecules converted
2 files output. The first is benzene.mop

where flag -m just tells that there multiple input files (for openbabel) to convert from .xyz to .mop. File pyridine.mop for instance reads

PUT KEYWORDS HERE
pyridine.xyz

C   1.43303 1  0.05159 1  0.00100 1
C   0.68800 1  1.22595 1  0.00151 1
C  -0.69424 1  1.12563 1  0.00218 1
N  -1.36237 1 -0.04853 1  0.00552 1
C  -0.61197 1 -1.17189 1  0.00692 1
C   0.77379 1 -1.17331 1  0.00332 1
H   2.51852 1  0.09036 1 -0.00113 1
H   1.17153 1  2.19630 1  0.00127 1
H  -1.31976 1  2.01344 1  0.00006 1
H  -1.17257 1 -2.10232 1  0.01145 1
H   1.32543 1 -2.10632 1  0.00270 1

which a UNIX like operating system (for instance Linux Debian) can adjust further by

sed -i 's/PUT KEYWORDS HERE/pm3 charge=0 cycles=200/g' *.mop

to instruct MOPAC about the level of theory, the charge, the maximal number of iterations to improve the geometry, etc. by substitution of the placeholder PUT KEYWORDS HERE openbabel added. (Openbabel has an optional -k flag to write the instructions for MOPAC into the .mop, too).