We present analyses of archival X-ray data obtained from the XMM-Newton satellite of an
intermediate polar V2400 Oph. The X-ray variations occur at the 1003-s synodic period which
is strongly indicated in the power spectrum of the time series. The blackbody temperature of
irradiated poles of the white dwarf atmosphere is found to be 90 eV, much higher than those found
in their synchronous analogues, the Polars. The EPIC-PN spectra shows the presence of soft X-ray
components. Blackbody-like emission, similar to that seen in soft IPs - however through higher
absorption, probably arises from the white dwarf surface. The temperature of the optically thin
postshock plasma is well constrained 13 keV, being strongly absorbed by dense material with an
equivalent hydrogen column density of 8.2×1022 cm -2, which partially cover 36±2 % of the Xray
source together with Fe Kα emission line. The new observations support V2400 Oph to be a
discless accreting system. We also present the phase-resolved spectroscopy in 0.1-10.0 keV energy
range and found that spectral parameters are phase dependent. Photometric and Polarimetric
observations of eighteen unidentified magnetic CVs were also carried out in 130 nights from 1-m
class telescopes of ARIES, Nainital. Among all these CVs we also present optical results of the four
candidates IPHASJ013+622, IPHASJ025+635, IPHASJ034+533 and IPHASJ051+294. Three of
the systems IPHASJ013+622, IPHASJ025+635 and IPHASJ051+294 were found to be eclipsing
from photometric data. Orbital periods of these CVs lie above the period gap of 2-3 h, which
indicates that these can be classified as an intermediate polars.